init

test/e2e/bb_counter.tape

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+# VHS E2E test for Babashka counter
+Output test/e2e/output/bb_counter.ascii
+
+Require bb
+
+Set Shell "bash"
+Set FontSize 14
+Set Width 800
+Set Height 400
+
+Type "bb counter"
+Enter
+Sleep 3s
+
+Type "k"
+Sleep 500ms
+Type "q"
+Sleep 1s

test/e2e/counter.tape

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+# VHS E2E test for counter example
+# Tests basic Elm architecture flow: render → input → update → render
+
+Output test/e2e/output/counter.gif
+Output test/e2e/output/counter.ascii
+
+Require clojure
+
+Set Shell "bash"
+Set FontSize 14
+Set Width 800
+Set Height 400
+Set Framerate 10
+
+# Run the counter example
+Type "clojure -A:dev -M -m examples.counter"
+Enter
+Sleep 2s
+
+# Test increment with 'k' key
+Type "k"
+Sleep 500ms
+Type "k"
+Sleep 500ms
+Type "k"
+Sleep 500ms
+
+# Test decrement with 'j' key
+Type "j"
+Sleep 500ms
+
+# Test up arrow
+Up
+Sleep 500ms
+
+# Test down arrow
+Down
+Sleep 500ms
+
+# Test reset with 'r'
+Type "r"
+Sleep 500ms
+
+# Quit with 'q'
+Type "q"
+Sleep 1s

test/e2e/output/bb_counter.ascii

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+────────────────────────────────────────────────────────────────────────────────
+>
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+────────────────────────────────────────────────────────────────────────────────
+>
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+────────────────────────────────────────────────────────────────────────────────
+>
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+────────────────────────────────────────────────────────────────────────────────
+>
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+────────────────────────────────────────────────────────────────────────────────
+> bb counter
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+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 0 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
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+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 0 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
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+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 1 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
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+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 1 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
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+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 1 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
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+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 1 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────

test/e2e/output/counter.ascii

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+>
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+────────────────────────────────────────────────────────────────────────────────
+>
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+────────────────────────────────────────────────────────────────────────────────
+>
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+────────────────────────────────────────────────────────────────────────────────
+>
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+────────────────────────────────────────────────────────────────────────────────
+>
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+────────────────────────────────────────────────────────────────────────────────
+>
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+────────────────────────────────────────────────────────────────────────────────
+> clojure -A:dev -M -m examples.counter
+
+
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+────────────────────────────────────────────────────────────────────────────────
+> clojure -A:dev -M -m examples.counter
+
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+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 0 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 1 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 1 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
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+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 2 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 2 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 3 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 3 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 2 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 2 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 3 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 3 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 2 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 2 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 0 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 0 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 0 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────
+╭──────────╮
+            │ Counter  │
+                        │          │
+                                    │ Count: 0 │
+                                                ╰──────────╯
+
+                                                            j/k or up/do
+wn: change value
+
+                r: reset  q: quit
+
+
+
+
+
+
+────────────────────────────────────────────────────────────────────────────────

test/tui/ansi_test.clj

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+(ns tui.ansi-test
+  "Unit tests for ANSI escape codes and string utilities."
+  (:require [clojure.test :refer [deftest testing is]]
+            [clojure.string :as str]
+            [tui.ansi :as ansi]))
+
+;; === Style Tests ===
+
+(deftest style-foreground-test
+  (testing "applies foreground colors"
+    (let [result (ansi/style "text" :fg :red)]
+      (is (str/includes? result "31m"))
+      (is (str/includes? result "text"))
+      (is (str/ends-with? result ansi/reset))))
+
+  (testing "applies bright foreground colors"
+    (let [result (ansi/style "text" :fg :bright-red)]
+      (is (str/includes? result "91m"))))
+
+  (testing "applies gray/grey alias"
+    (let [gray (ansi/style "text" :fg :gray)
+          grey (ansi/style "text" :fg :grey)]
+      (is (= gray grey))
+      (is (str/includes? gray "90m")))))
+
+(deftest style-background-test
+  (testing "applies background colors"
+    (let [result (ansi/style "text" :bg :blue)]
+      (is (str/includes? result "44m"))
+      (is (str/includes? result "text")))))
+
+(deftest style-attributes-test
+  (testing "applies bold"
+    (let [result (ansi/style "text" :bold true)]
+      (is (str/includes? result "1m"))))
+
+  (testing "applies dim"
+    (let [result (ansi/style "text" :dim true)]
+      (is (str/includes? result "2m"))))
+
+  (testing "applies italic"
+    (let [result (ansi/style "text" :italic true)]
+      (is (str/includes? result "3m"))))
+
+  (testing "applies underline"
+    (let [result (ansi/style "text" :underline true)]
+      (is (str/includes? result "4m"))))
+
+  (testing "applies inverse"
+    (let [result (ansi/style "text" :inverse true)]
+      (is (str/includes? result "7m"))))
+
+  (testing "applies strikethrough"
+    (let [result (ansi/style "text" :strike true)]
+      (is (str/includes? result "9m")))))
+
+(deftest style-combined-test
+  (testing "combines multiple styles"
+    (let [result (ansi/style "text" :fg :red :bold true :underline true)]
+      (is (str/includes? result "31"))   ; Red
+      (is (str/includes? result "1"))    ; Bold
+      (is (str/includes? result "4"))))) ; Underline
+
+(deftest style-no-styles-test
+  (testing "returns plain text when no styles"
+    (is (= "text" (ansi/style "text")))))
+
+;; === Color Helper Tests ===
+
+(deftest fg-helper-test
+  (testing "fg helper applies foreground color"
+    (let [result (ansi/fg :green "text")]
+      (is (str/includes? result "32m"))
+      (is (str/includes? result "text")))))
+
+(deftest bg-helper-test
+  (testing "bg helper applies background color"
+    (let [result (ansi/bg :yellow "text")]
+      (is (str/includes? result "43m"))
+      (is (str/includes? result "text")))))
+
+;; === 256 Color Tests ===
+
+(deftest fg-256-test
+  (testing "applies 256-color foreground"
+    (let [result (ansi/fg-256 196 "text")]
+      (is (str/includes? result "38;5;196m"))
+      (is (str/includes? result "text")))))
+
+(deftest bg-256-test
+  (testing "applies 256-color background"
+    (let [result (ansi/bg-256 21 "text")]
+      (is (str/includes? result "48;5;21m"))
+      (is (str/includes? result "text")))))
+
+;; === True Color Tests ===
+
+(deftest fg-rgb-test
+  (testing "applies RGB foreground"
+    (let [result (ansi/fg-rgb 255 128 64 "text")]
+      (is (str/includes? result "38;2;255;128;64m"))
+      (is (str/includes? result "text")))))
+
+(deftest bg-rgb-test
+  (testing "applies RGB background"
+    (let [result (ansi/bg-rgb 0 128 255 "text")]
+      (is (str/includes? result "48;2;0;128;255m"))
+      (is (str/includes? result "text")))))
+
+;; === String Utility Tests ===
+
+(deftest visible-length-test
+  (testing "returns length of plain text"
+    (is (= 5 (ansi/visible-length "hello")))
+    (is (= 0 (ansi/visible-length ""))))
+
+  (testing "excludes ANSI codes from length"
+    (let [styled (ansi/style "hello" :fg :red :bold true)]
+      (is (= 5 (ansi/visible-length styled)))))
+
+  (testing "handles multiple ANSI sequences"
+    (let [text (str (ansi/fg :red "red") (ansi/fg :blue "blue"))]
+      (is (= 7 (ansi/visible-length text))))))
+
+(deftest pad-right-test
+  (testing "pads string to width"
+    (is (= "hi   " (ansi/pad-right "hi" 5)))
+    (is (= "hello" (ansi/pad-right "hello" 5))))
+
+  (testing "does not truncate if longer"
+    (is (= "hello" (ansi/pad-right "hello" 3))))
+
+  (testing "handles styled text"
+    (let [styled (ansi/style "hi" :fg :red)
+          padded (ansi/pad-right styled 5)]
+      (is (= 5 (ansi/visible-length padded))))))
+
+(deftest pad-left-test
+  (testing "pads string on left"
+    (is (= "   hi" (ansi/pad-left "hi" 5)))
+    (is (= "hello" (ansi/pad-left "hello" 5))))
+
+  (testing "does not truncate if longer"
+    (is (= "hello" (ansi/pad-left "hello" 3)))))
+
+(deftest pad-center-test
+  (testing "centers string"
+    (is (= " hi  " (ansi/pad-center "hi" 5)))
+    (is (= "  hi  " (ansi/pad-center "hi" 6))))
+
+  (testing "handles odd padding"
+    (is (= " x " (ansi/pad-center "x" 3)))))
+
+(deftest truncate-test
+  (testing "truncates long strings"
+    (is (= "hel\u2026" (ansi/truncate "hello" 4)))
+    (is (= "h\u2026" (ansi/truncate "hello" 2))))
+
+  (testing "does not truncate short strings"
+    (is (= "hi" (ansi/truncate "hi" 5)))
+    (is (= "hello" (ansi/truncate "hello" 5)))))
+
+;; === Box Characters Tests ===
+
+(deftest box-chars-test
+  (testing "all border styles have required characters"
+    (doseq [[style chars] ansi/box-chars]
+      (is (contains? chars :tl) (str style " missing :tl"))
+      (is (contains? chars :tr) (str style " missing :tr"))
+      (is (contains? chars :bl) (str style " missing :bl"))
+      (is (contains? chars :br) (str style " missing :br"))
+      (is (contains? chars :h) (str style " missing :h"))
+      (is (contains? chars :v) (str style " missing :v")))))
+
+;; === Escape Sequence Constants Tests ===
+
+(deftest escape-sequences-test
+  (testing "escape sequences are strings"
+    (is (string? ansi/clear-screen))
+    (is (string? ansi/clear-line))
+    (is (string? ansi/cursor-home))
+    (is (string? ansi/hide-cursor))
+    (is (string? ansi/show-cursor))
+    (is (string? ansi/enter-alt-screen))
+    (is (string? ansi/exit-alt-screen)))
+
+  (testing "escape sequences start with ESC"
+    (is (str/starts-with? ansi/clear-screen "\u001b"))
+    (is (str/starts-with? ansi/cursor-home "\u001b"))))
+
+(deftest cursor-movement-test
+  (testing "cursor-to generates correct sequence"
+    (is (= "\u001b[5;10H" (ansi/cursor-to 5 10))))
+
+  (testing "cursor movement functions"
+    (is (= "\u001b[3A" (ansi/cursor-up 3)))
+    (is (= "\u001b[2B" (ansi/cursor-down 2)))
+    (is (= "\u001b[4C" (ansi/cursor-forward 4)))
+    (is (= "\u001b[1D" (ansi/cursor-back 1)))))

test/tui/api_test.clj

@@ -0,0 +1,577 @@
+(ns tui.api-test
+  "Comprehensive unit tests for user-facing API functions.
+   Test cases derived from actual usage patterns in examples."
+  (:require [clojure.test :refer [deftest testing is are]]
+            [clojure.string :as str]
+            [tui.core :as tui]
+            [tui.render :as render]
+            [tui.input :as input]))
+
+;; =============================================================================
+;; KEY MATCHING TESTS (tui/key=)
+;; Patterns from: counter, timer, list-selection, spinner, views, http
+;; =============================================================================
+
+(deftest key=-character-keys-test
+  (testing "from counter: matching q for quit"
+    (is (tui/key= [:key {:char \q}] "q"))
+    (is (not (tui/key= [:key {:char \a}] "q"))))
+
+  (testing "from counter: matching k/j for navigation"
+    (is (tui/key= [:key {:char \k}] "k"))
+    (is (tui/key= [:key {:char \j}] "j")))
+
+  (testing "from counter: matching r for reset"
+    (is (tui/key= [:key {:char \r}] "r")))
+
+  (testing "from timer: matching space for pause/resume"
+    (is (tui/key= [:key {:char \space}] " "))
+    (is (tui/key= [:key {:char \space}] " ")))
+
+  (testing "from views: matching b for back, y/n for confirm"
+    (is (tui/key= [:key {:char \b}] "b"))
+    (is (tui/key= [:key {:char \y}] "y"))
+    (is (tui/key= [:key {:char \n}] "n"))))
+
+(deftest key=-arrow-keys-test
+  (testing "from counter/list-selection: up/down arrows"
+    (is (tui/key= [:key :up] :up))
+    (is (tui/key= [:key :down] :down))
+    (is (not (tui/key= [:key :up] :down)))
+    (is (not (tui/key= [:key :left] :up))))
+
+  (testing "left/right arrows"
+    (is (tui/key= [:key :left] :left))
+    (is (tui/key= [:key :right] :right))))
+
+(deftest key=-special-keys-test
+  (testing "from list-selection/http: enter key"
+    (is (tui/key= [:key :enter] :enter)))
+
+  (testing "from views: escape key"
+    (is (tui/key= [:key :escape] :escape)))
+
+  (testing "from spinner: tab key"
+    (is (tui/key= [:key :tab] :tab)))
+
+  (testing "backspace key"
+    (is (tui/key= [:key :backspace] :backspace))))
+
+(deftest key=-ctrl-combos-test
+  (testing "from all examples: ctrl+c for quit"
+    (is (tui/key= [:key {:ctrl true :char \c}] [:ctrl \c])))
+
+  (testing "other ctrl combinations"
+    (is (tui/key= [:key {:ctrl true :char \x}] [:ctrl \x]))
+    (is (tui/key= [:key {:ctrl true :char \z}] [:ctrl \z]))
+    (is (tui/key= [:key {:ctrl true :char \a}] [:ctrl \a])))
+
+  (testing "ctrl combo does not match plain char"
+    (is (not (tui/key= [:key {:ctrl true :char \c}] "c")))
+    (is (not (tui/key= [:key {:char \c}] [:ctrl \c])))))
+
+(deftest key=-alt-combos-test
+  (testing "alt+char combinations"
+    (is (tui/key= [:key {:alt true :char \x}] [:alt \x]))
+    (is (tui/key= [:key {:alt true :char \a}] [:alt \a])))
+
+  (testing "alt combo does not match plain char"
+    (is (not (tui/key= [:key {:alt true :char \x}] "x")))
+    (is (not (tui/key= [:key {:char \x}] [:alt \x])))))
+
+(deftest key=-non-key-messages-test
+  (testing "from timer/spinner: tick messages are not keys"
+    (is (not (tui/key= [:tick 123456789] "q")))
+    (is (not (tui/key= [:tick 123456789] :enter))))
+
+  (testing "from http: custom messages are not keys"
+    (is (not (tui/key= [:http-success 200] "q")))
+    (is (not (tui/key= [:http-error "timeout"] :enter))))
+
+  (testing "quit command is not a key"
+    (is (not (tui/key= [:quit] "q")))))
+
+;; =============================================================================
+;; COMMAND TESTS
+;; Patterns from: timer, spinner, http
+;; =============================================================================
+
+(deftest quit-command-test
+  (testing "from all examples: tui/quit is [:quit]"
+    (is (= [:quit] tui/quit))
+    (is (vector? tui/quit))
+    (is (= :quit (first tui/quit)))))
+
+(deftest tick-command-test
+  (testing "from timer: tick with 1000ms"
+    (is (= [:tick 1000] (tui/tick 1000))))
+
+  (testing "from spinner: tick with 80ms"
+    (is (= [:tick 80] (tui/tick 80))))
+
+  (testing "tick with various intervals"
+    (are [ms] (= [:tick ms] (tui/tick ms))
+      0 1 10 100 500 1000 5000 60000)))
+
+(deftest batch-command-test
+  (testing "batch two commands"
+    (let [cmd (tui/batch (tui/tick 100) tui/quit)]
+      (is (= [:batch [:tick 100] [:quit]] cmd))))
+
+  (testing "batch three commands"
+    (let [cmd (tui/batch (tui/tick 50) (tui/tick 100) tui/quit)]
+      (is (= [:batch [:tick 50] [:tick 100] [:quit]] cmd))))
+
+  (testing "batch filters nil"
+    (is (= [:batch [:tick 100]] (tui/batch nil (tui/tick 100) nil)))
+    (is (= [:batch] (tui/batch nil nil nil))))
+
+  (testing "batch with single command"
+    (is (= [:batch tui/quit] (tui/batch tui/quit)))))
+
+(deftest sequentially-command-test
+  (testing "sequentially two commands"
+    (let [cmd (tui/sequentially (tui/tick 100) tui/quit)]
+      (is (= [:seq [:tick 100] [:quit]] cmd))))
+
+  (testing "sequentially filters nil"
+    (is (= [:seq [:tick 100]] (tui/sequentially nil (tui/tick 100) nil))))
+
+  (testing "sequentially with functions"
+    (let [f (fn [] :msg)
+          cmd (tui/sequentially f tui/quit)]
+      (is (= 3 (count cmd)))
+      (is (= :seq (first cmd)))
+      (is (fn? (second cmd))))))
+
+(deftest send-msg-command-test
+  (testing "from http pattern: send-msg creates function"
+    (let [cmd (tui/send-msg [:http-success 200])]
+      (is (fn? cmd))
+      (is (= [:http-success 200] (cmd)))))
+
+  (testing "send-msg with map"
+    (let [cmd (tui/send-msg {:type :custom :data 42})]
+      (is (= {:type :custom :data 42} (cmd)))))
+
+  (testing "send-msg with keyword"
+    (let [cmd (tui/send-msg :done)]
+      (is (= :done (cmd))))))
+
+(deftest custom-command-function-test
+  (testing "from http: custom async command pattern"
+    (let [fetch-result (atom nil)
+          cmd (fn []
+                (reset! fetch-result :fetched)
+                [:http-success 200])]
+      ;; Execute command
+      (is (= [:http-success 200] (cmd)))
+      (is (= :fetched @fetch-result)))))
+
+;; =============================================================================
+;; UPDATE FUNCTION PATTERNS
+;; Testing the [model cmd] return contract
+;; =============================================================================
+
+(deftest update-returns-tuple-test
+  (testing "update always returns [model cmd] tuple"
+    (let [model {:count 0}
+          ;; Counter-style update
+          update-fn (fn [m msg]
+                      (cond
+                        (tui/key= msg "q") [m tui/quit]
+                        (tui/key= msg :up) [(update m :count inc) nil]
+                        :else [m nil]))]
+
+      ;; Quit returns original model + quit command
+      (let [[new-model cmd] (update-fn model [:key {:char \q}])]
+        (is (= model new-model))
+        (is (= tui/quit cmd)))
+
+      ;; Up returns modified model + nil command
+      (let [[new-model cmd] (update-fn model [:key :up])]
+        (is (= {:count 1} new-model))
+        (is (nil? cmd)))
+
+      ;; Unknown key returns unchanged model + nil command
+      (let [[new-model cmd] (update-fn model [:key {:char \x}])]
+        (is (= model new-model))
+        (is (nil? cmd))))))
+
+(deftest counter-update-pattern-test
+  (testing "counter increment/decrement pattern"
+    (let [update-fn (fn [{:keys [count] :as model} msg]
+                      (cond
+                        (or (tui/key= msg :up)
+                            (tui/key= msg "k"))
+                        [(update model :count inc) nil]
+
+                        (or (tui/key= msg :down)
+                            (tui/key= msg "j"))
+                        [(update model :count dec) nil]
+
+                        (tui/key= msg "r")
+                        [(assoc model :count 0) nil]
+
+                        :else
+                        [model nil]))]
+
+      ;; Test sequence: up, up, down, reset
+      (let [m0 {:count 0}
+            [m1 _] (update-fn m0 [:key :up])
+            [m2 _] (update-fn m1 [:key {:char \k}])
+            [m3 _] (update-fn m2 [:key :down])
+            [m4 _] (update-fn m3 [:key {:char \r}])]
+        (is (= 1 (:count m1)))
+        (is (= 2 (:count m2)))
+        (is (= 1 (:count m3)))
+        (is (= 0 (:count m4)))))))
+
+(deftest timer-update-pattern-test
+  (testing "timer tick handling pattern"
+    (let [update-fn (fn [{:keys [seconds running] :as model} msg]
+                      (cond
+                        (= (first msg) :tick)
+                        (if running
+                          (let [new-seconds (dec seconds)]
+                            (if (<= new-seconds 0)
+                              [(assoc model :seconds 0 :done true :running false) nil]
+                              [(assoc model :seconds new-seconds) (tui/tick 1000)]))
+                          [model nil])
+
+                        (tui/key= msg " ")
+                        (let [new-running (not running)]
+                          [(assoc model :running new-running)
+                           (when new-running (tui/tick 1000))])
+
+                        :else
+                        [model nil]))]
+
+      ;; Test tick countdown
+      (let [m0 {:seconds 3 :running true :done false}
+            [m1 c1] (update-fn m0 [:tick 123])
+            [m2 c2] (update-fn m1 [:tick 123])
+            [m3 c3] (update-fn m2 [:tick 123])]
+        (is (= 2 (:seconds m1)))
+        (is (= [:tick 1000] c1))
+        (is (= 1 (:seconds m2)))
+        (is (= [:tick 1000] c2))
+        (is (= 0 (:seconds m3)))
+        (is (:done m3))
+        (is (not (:running m3)))
+        (is (nil? c3)))
+
+      ;; Test pause/resume
+      (let [m0 {:seconds 5 :running true :done false}
+            [m1 c1] (update-fn m0 [:key {:char \space}])
+            [m2 c2] (update-fn m1 [:key {:char \space}])]
+        (is (not (:running m1)))
+        (is (nil? c1))
+        (is (:running m2))
+        (is (= [:tick 1000] c2))))))
+
+(deftest list-selection-update-pattern-test
+  (testing "cursor navigation with bounds"
+    (let [items ["a" "b" "c" "d"]
+          update-fn (fn [{:keys [cursor] :as model} msg]
+                      (cond
+                        (or (tui/key= msg :up) (tui/key= msg "k"))
+                        [(update model :cursor #(max 0 (dec %))) nil]
+
+                        (or (tui/key= msg :down) (tui/key= msg "j"))
+                        [(update model :cursor #(min (dec (count items)) (inc %))) nil]
+
+                        :else
+                        [model nil]))]
+
+      ;; Test bounds
+      (let [m0 {:cursor 0}
+            [m1 _] (update-fn m0 [:key :up])      ; Can't go below 0
+            [m2 _] (update-fn m1 [:key :down])
+            [m3 _] (update-fn m2 [:key :down])
+            [m4 _] (update-fn m3 [:key :down])
+            [m5 _] (update-fn m4 [:key :down])]   ; Can't go above 3
+        (is (= 0 (:cursor m1)))
+        (is (= 1 (:cursor m2)))
+        (is (= 2 (:cursor m3)))
+        (is (= 3 (:cursor m4)))
+        (is (= 3 (:cursor m5))))))
+
+  (testing "toggle selection pattern"
+    (let [update-fn (fn [{:keys [cursor] :as model} msg]
+                      (if (tui/key= msg " ")
+                        [(update model :selected
+                                 #(if (contains? % cursor)
+                                    (disj % cursor)
+                                    (conj % cursor)))
+                         nil]
+                        [model nil]))]
+
+      (let [m0 {:cursor 0 :selected #{}}
+            [m1 _] (update-fn m0 [:key {:char \space}])
+            [m2 _] (update-fn (assoc m1 :cursor 2) [:key {:char \space}])
+            [m3 _] (update-fn (assoc m2 :cursor 0) [:key {:char \space}])]
+        (is (= #{0} (:selected m1)))
+        (is (= #{0 2} (:selected m2)))
+        (is (= #{2} (:selected m3)))))))
+
+(deftest views-state-machine-pattern-test
+  (testing "view state transitions"
+    (let [update-fn (fn [{:keys [view] :as model} msg]
+                      (case view
+                        :menu
+                        (cond
+                          (tui/key= msg :enter)
+                          [(assoc model :view :detail) nil]
+                          (tui/key= msg "q")
+                          [(assoc model :view :confirm) nil]
+                          :else [model nil])
+
+                        :detail
+                        (cond
+                          (or (tui/key= msg :escape) (tui/key= msg "b"))
+                          [(assoc model :view :menu) nil]
+                          (tui/key= msg "q")
+                          [(assoc model :view :confirm) nil]
+                          :else [model nil])
+
+                        :confirm
+                        (cond
+                          (tui/key= msg "y")
+                          [model tui/quit]
+                          (tui/key= msg "n")
+                          [(assoc model :view :detail) nil]
+                          :else [model nil])))]
+
+      ;; Menu -> Detail -> Confirm -> Quit
+      (let [m0 {:view :menu}
+            [m1 _] (update-fn m0 [:key :enter])
+            [m2 _] (update-fn m1 [:key {:char \q}])
+            [m3 c3] (update-fn m2 [:key {:char \y}])]
+        (is (= :detail (:view m1)))
+        (is (= :confirm (:view m2)))
+        (is (= tui/quit c3)))
+
+      ;; Detail -> Menu (back)
+      (let [m0 {:view :detail}
+            [m1 _] (update-fn m0 [:key :escape])]
+        (is (= :menu (:view m1)))))))
+
+(deftest http-async-pattern-test
+  (testing "HTTP state machine pattern"
+    (let [update-fn (fn [{:keys [state url] :as model} msg]
+                      (cond
+                        (and (= state :idle) (tui/key= msg :enter))
+                        [(assoc model :state :loading)
+                         (fn [] [:http-success 200])]
+
+                        (= (first msg) :http-success)
+                        [(assoc model :state :success :status (second msg)) nil]
+
+                        (= (first msg) :http-error)
+                        [(assoc model :state :error :error (second msg)) nil]
+
+                        (tui/key= msg "r")
+                        [(assoc model :state :idle :status nil :error nil) nil]
+
+                        :else
+                        [model nil]))]
+
+      ;; Idle -> Loading
+      (let [m0 {:state :idle :url "http://test.com"}
+            [m1 c1] (update-fn m0 [:key :enter])]
+        (is (= :loading (:state m1)))
+        (is (fn? c1)))
+
+      ;; Loading -> Success
+      (let [m0 {:state :loading}
+            [m1 _] (update-fn m0 [:http-success 200])]
+        (is (= :success (:state m1)))
+        (is (= 200 (:status m1))))
+
+      ;; Loading -> Error
+      (let [m0 {:state :loading}
+            [m1 _] (update-fn m0 [:http-error "Connection refused"])]
+        (is (= :error (:state m1)))
+        (is (= "Connection refused" (:error m1))))
+
+      ;; Reset
+      (let [m0 {:state :error :error "timeout"}
+            [m1 _] (update-fn m0 [:key {:char \r}])]
+        (is (= :idle (:state m1)))
+        (is (nil? (:error m1)))))))
+
+;; =============================================================================
+;; RENDER TESTS
+;; Testing hiccup patterns from examples
+;; =============================================================================
+
+(deftest render-text-styles-test
+  (testing "from counter: bold title"
+    (let [result (render/render [:text {:bold true} "Counter"])]
+      (is (str/includes? result "Counter"))
+      (is (str/includes? result "\u001b[1m"))))
+
+  (testing "from counter: conditional fg color"
+    (let [pos-result (render/render [:text {:fg :green} "Count: 5"])
+          neg-result (render/render [:text {:fg :red} "Count: -3"])
+          zero-result (render/render [:text {:fg :default} "Count: 0"])]
+      (is (str/includes? pos-result "32m"))   ; Green
+      (is (str/includes? neg-result "31m"))   ; Red
+      (is (str/includes? zero-result "Count: 0"))))
+
+  (testing "from timer: multiple styles"
+    (let [result (render/render [:text {:fg :cyan :bold true} "00:10"])]
+      (is (str/includes? result "36"))        ; Cyan
+      (is (str/includes? result "1"))))       ; Bold
+
+  (testing "from views: italic style"
+    (let [result (render/render [:text {:fg :gray :italic true} "Help text"])]
+      (is (str/includes? result "3m")))))     ; Italic
+
+(deftest render-layout-patterns-test
+  (testing "from counter: col with gap"
+    (let [result (render/render [:col {:gap 1}
+                                 [:text "Line 1"]
+                                 [:text "Line 2"]])]
+      (is (str/includes? result "Line 1"))
+      (is (str/includes? result "Line 2"))
+      ;; Gap of 1 means extra newline between items
+      (is (str/includes? result "\n\n"))))
+
+  (testing "from list-selection: row with gap"
+    (let [result (render/render [:row {:gap 1}
+                                 [:text ">"]
+                                 [:text "[x]"]
+                                 [:text "Pizza"]])]
+      (is (str/includes? result ">"))
+      (is (str/includes? result "[x]"))
+      (is (str/includes? result "Pizza"))))
+
+  (testing "from views: nested col in row"
+    (let [result (render/render [:row {:gap 2}
+                                 [:text "A"]
+                                 [:text "B"]
+                                 [:text "C"]])]
+      (is (= "A  B  C" result)))))
+
+(deftest render-box-patterns-test
+  (testing "from counter: rounded border with padding"
+    (let [result (render/render [:box {:border :rounded :padding [0 1]}
+                                 [:text "Content"]])]
+      (is (str/includes? result "╭"))         ; Rounded corner
+      (is (str/includes? result "╯"))
+      (is (str/includes? result "Content"))))
+
+  (testing "from list-selection: box with title"
+    (let [result (render/render [:box {:border :rounded :title "Menu"}
+                                 [:text "Item 1"]])]
+      (is (str/includes? result "Menu"))
+      (is (str/includes? result "Item 1"))))
+
+  (testing "from views: double border"
+    (let [result (render/render [:box {:border :double}
+                                 [:text "Detail"]])]
+      (is (str/includes? result "╔"))         ; Double corner
+      (is (str/includes? result "║"))))       ; Double vertical
+
+  (testing "box with complex padding"
+    (let [result (render/render [:box {:padding [1 2]}
+                                 [:text "X"]])]
+      ;; Should have vertical and horizontal padding
+      (is (str/includes? result "X")))))
+
+(deftest render-dynamic-content-test
+  (testing "from list-selection: generating items with into"
+    ;; Use into to build hiccup with dynamic children
+    (let [items ["Pizza" "Sushi" "Tacos"]
+          result (render/render
+                  (into [:col]
+                        (for [item items]
+                          [:text item])))]
+      (is (str/includes? result "Pizza"))
+      (is (str/includes? result "Sushi"))
+      (is (str/includes? result "Tacos"))))
+
+  (testing "conditional rendering"
+    (let [loading? true
+          result (render/render
+                  (if loading?
+                    [:text {:fg :yellow} "Loading..."]
+                    [:text {:fg :green} "Done"]))]
+      (is (str/includes? result "Loading..."))))
+
+  (testing "from http: case-based view selection"
+    (let [render-state (fn [state]
+                         (render/render
+                          (case state
+                            :idle [:text "Press enter"]
+                            :loading [:text {:fg :yellow} "Fetching..."]
+                            :success [:text {:fg :green} "Done"]
+                            :error [:text {:fg :red} "Failed"])))]
+      (is (str/includes? (render-state :idle) "Press enter"))
+      (is (str/includes? (render-state :loading) "Fetching"))
+      (is (str/includes? (render-state :success) "Done"))
+      (is (str/includes? (render-state :error) "Failed")))))
+
+(deftest render-complex-view-test
+  (testing "from counter: full view structure"
+    (let [view (fn [{:keys [count]}]
+                 [:col {:gap 1}
+                  [:box {:border :rounded :padding [0 1]}
+                   [:col
+                    [:text {:bold true} "Counter"]
+                    [:text ""]
+                    [:text {:fg (cond
+                                  (pos? count) :green
+                                  (neg? count) :red
+                                  :else :default)}
+                     (str "Count: " count)]]]
+                  [:text {:fg :gray} "j/k: change value"]])
+          result (render/render (view {:count 5}))]
+      (is (str/includes? result "Counter"))
+      (is (str/includes? result "Count: 5"))
+      (is (str/includes? result "j/k: change value"))
+      (is (str/includes? result "╭"))))        ; Has box
+
+  (testing "from list-selection: cursor indicator"
+    (let [render-item (fn [idx cursor item selected]
+                        (let [is-cursor (= idx cursor)
+                              is-selected (contains? selected idx)]
+                          [:row {:gap 1}
+                           [:text (if is-cursor ">" " ")]
+                           [:text (if is-selected "[x]" "[ ]")]
+                           [:text {:bold is-cursor} item]]))
+          result (render/render
+                  [:col
+                   (render-item 0 0 "Pizza" #{0})
+                   (render-item 1 0 "Sushi" #{})
+                   (render-item 2 0 "Tacos" #{})])]
+      ;; Note: bold text includes ANSI codes, so check for components
+      (is (str/includes? result "> [x]"))
+      (is (str/includes? result "Pizza"))
+      (is (str/includes? result "[ ] Sushi"))
+      (is (str/includes? result "[ ] Tacos")))))
+
+;; =============================================================================
+;; KEY-STR TESTS
+;; =============================================================================
+
+(deftest key-str-comprehensive-test
+  (testing "character keys"
+    (is (= "q" (tui/key-str [:key {:char \q}])))
+    (is (= " " (tui/key-str [:key {:char \space}]))))
+
+  (testing "special keys"
+    (is (= "enter" (tui/key-str [:key :enter])))
+    (is (= "escape" (tui/key-str [:key :escape])))
+    (is (= "tab" (tui/key-str [:key :tab])))
+    (is (= "backspace" (tui/key-str [:key :backspace])))
+    (is (= "up" (tui/key-str [:key :up])))
+    (is (= "down" (tui/key-str [:key :down])))
+    (is (= "left" (tui/key-str [:key :left])))
+    (is (= "right" (tui/key-str [:key :right]))))
+
+  (testing "modifier keys"
+    (is (= "ctrl+c" (tui/key-str [:key {:ctrl true :char \c}])))
+    (is (= "alt+x" (tui/key-str [:key {:alt true :char \x}])))))

test/tui/core_test.clj

@@ -0,0 +1,173 @@
+(ns tui.core-test
+  "Integration tests for the TUI engine.
+   Tests the update loop, command handling, and full render pipeline."
+  (:require [clojure.test :refer [deftest testing is]]
+            [clojure.core.async :as async :refer [chan >!! <!! timeout alt!! close!]]
+            [tui.core :as tui]
+            [tui.render :as render]))
+
+;; === Command Tests ===
+
+(deftest quit-command-test
+  (testing "quit command is correct vector"
+    (is (= [:quit] tui/quit))))
+
+(deftest tick-command-test
+  (testing "tick creates correct command"
+    (is (= [:tick 100] (tui/tick 100)))
+    (is (= [:tick 1000] (tui/tick 1000)))))
+
+(deftest batch-command-test
+  (testing "batch combines commands"
+    (is (= [:batch [:tick 100] [:quit]] (tui/batch (tui/tick 100) tui/quit))))
+
+  (testing "batch filters nil commands"
+    (is (= [:batch [:tick 100]] (tui/batch nil (tui/tick 100) nil)))))
+
+(deftest sequentially-command-test
+  (testing "sequentially creates seq command"
+    (is (= [:seq [:tick 100] [:quit]] (tui/sequentially (tui/tick 100) tui/quit))))
+
+  (testing "sequentially filters nil commands"
+    (is (= [:seq [:tick 100]] (tui/sequentially nil (tui/tick 100) nil)))))
+
+(deftest send-msg-command-test
+  (testing "send-msg creates function that returns message"
+    (let [cmd (tui/send-msg {:type :custom :data 42})]
+      (is (fn? cmd))
+      (is (= {:type :custom :data 42} (cmd))))))
+
+;; === Key Matching Tests ===
+
+(deftest key=-test
+  (testing "key= delegates to input/key-match?"
+    (is (tui/key= [:key {:char \q}] "q"))
+    (is (tui/key= [:key :enter] :enter))
+    (is (tui/key= [:key {:ctrl true :char \c}] [:ctrl \c]))
+    (is (not (tui/key= [:key {:char \a}] "b")))))
+
+(deftest key-str-test
+  (testing "key-str converts key to string"
+    (is (= "q" (tui/key-str [:key {:char \q}])))
+    (is (= "enter" (tui/key-str [:key :enter])))))
+
+;; === Full Pipeline Tests ===
+
+(deftest render-pipeline-test
+  (testing "model -> view -> render produces valid output"
+    (let [model {:count 5}
+          view (fn [{:keys [count]}]
+                 [:col
+                  [:text {:bold true} "Counter"]
+                  [:text (str "Count: " count)]])
+          rendered (render/render (view model))]
+      (is (string? rendered))
+      (is (clojure.string/includes? rendered "Counter"))
+      (is (clojure.string/includes? rendered "Count: 5")))))
+
+(deftest update-function-contract-test
+  (testing "update function returns [model cmd] tuple"
+    (let [update-fn (fn [model msg]
+                      (cond
+                        (tui/key= msg "q") [model tui/quit]
+                        (tui/key= msg :up) [(update model :n inc) nil]
+                        :else [model nil]))
+          model {:n 0}]
+
+      ;; Test quit returns command
+      (let [[new-model cmd] (update-fn model [:key {:char \q}])]
+        (is (= model new-model))
+        (is (= [:quit] cmd)))
+
+      ;; Test up returns updated model
+      (let [[new-model cmd] (update-fn model [:key :up])]
+        (is (= {:n 1} new-model))
+        (is (nil? cmd)))
+
+      ;; Test unknown key returns model unchanged
+      (let [[new-model cmd] (update-fn model [:key {:char \x}])]
+        (is (= model new-model))
+        (is (nil? cmd))))))
+
+;; === Command Execution Tests ===
+;; These test the internal command execution logic
+
+(deftest execute-quit-command-test
+  (testing "quit command puts :quit on channel"
+    (let [msg-chan (chan 1)]
+      (#'tui/execute-cmd! [:quit] msg-chan)
+      (let [result (alt!!
+                     msg-chan ([v] v)
+                     (timeout 100) :timeout)]
+        (is (= [:quit] result)))
+      (close! msg-chan))))
+
+(deftest execute-tick-command-test
+  (testing "tick command sends :tick message after delay"
+    (let [msg-chan (chan 1)]
+      (#'tui/execute-cmd! [:tick 50] msg-chan)
+      ;; Should not receive immediately
+      (let [immediate (alt!!
+                        msg-chan ([v] v)
+                        (timeout 10) :timeout)]
+        (is (= :timeout immediate)))
+      ;; Should receive after delay
+      (let [delayed (alt!!
+                      msg-chan ([v] v)
+                      (timeout 200) :timeout)]
+        (is (vector? delayed))
+        (is (= :tick (first delayed))))
+      (close! msg-chan))))
+
+(deftest execute-function-command-test
+  (testing "function command executes and sends result"
+    (let [msg-chan (chan 1)
+          cmd (fn [] {:custom :message})]
+      (#'tui/execute-cmd! cmd msg-chan)
+      (let [result (alt!!
+                     msg-chan ([v] v)
+                     (timeout 100) :timeout)]
+        (is (= {:custom :message} result)))
+      (close! msg-chan))))
+
+(deftest execute-batch-command-test
+  (testing "batch executes multiple commands"
+    (let [msg-chan (chan 10)]
+      (#'tui/execute-cmd! [:batch
+                           (fn [] :msg1)
+                           (fn [] :msg2)]
+                          msg-chan)
+      ;; Give time for async execution
+      (Thread/sleep 50)
+      (let [results (loop [msgs []]
+                      (let [msg (alt!!
+                                  msg-chan ([v] v)
+                                  (timeout 10) nil)]
+                        (if msg
+                          (recur (conj msgs msg))
+                          msgs)))]
+        (is (= #{:msg1 :msg2} (set results))))
+      (close! msg-chan))))
+
+(deftest execute-nil-command-test
+  (testing "nil command does nothing"
+    (let [msg-chan (chan 1)]
+      (#'tui/execute-cmd! nil msg-chan)
+      (let [result (alt!!
+                     msg-chan ([v] v)
+                     (timeout 50) :timeout)]
+        (is (= :timeout result)))
+      (close! msg-chan))))
+
+;; === Defapp Macro Tests ===
+
+(deftest defapp-macro-test
+  (testing "defapp creates app map"
+    (tui/defapp test-app
+      :init {:count 0}
+      :update (fn [m msg] [m nil])
+      :view (fn [m] [:text "test"]))
+    (is (map? test-app))
+    (is (= {:count 0} (:init test-app)))
+    (is (fn? (:update test-app)))
+    (is (fn? (:view test-app)))))

test/tui/edge_cases_test.clj

@@ -0,0 +1,403 @@
+(ns tui.edge-cases-test
+  "Edge case tests for all TUI modules.
+   Tests boundary conditions, error handling, and unusual inputs."
+  (:require [clojure.test :refer [deftest testing is are]]
+            [clojure.string :as str]
+            [tui.core :as tui]
+            [tui.render :as render]
+            [tui.input :as input]
+            [tui.ansi :as ansi]))
+
+;; =============================================================================
+;; RENDER EDGE CASES
+;; =============================================================================
+
+(deftest render-empty-elements-test
+  (testing "empty col renders as empty string"
+    (is (= "" (render/render [:col]))))
+
+  (testing "empty row renders as empty string"
+    (is (= "" (render/render [:row]))))
+
+  (testing "empty text renders as empty string"
+    (is (= "" (render/render [:text]))))
+
+  (testing "nil renders as empty string"
+    (is (= "" (render/render nil)))))
+
+(deftest render-nested-empty-test
+  (testing "nested empty elements produce minimal output"
+    ;; Col with empty rows produces newlines between them
+    (is (= "\n" (render/render [:col [:row] [:row]])))
+    ;; Row with empty cols produces empty string (no gap)
+    (is (= "" (render/render [:row [:col] [:col]])))))
+
+(deftest render-single-element-test
+  (testing "single element col"
+    (is (= "hello" (render/render [:col "hello"]))))
+
+  (testing "single element row"
+    (is (= "hello" (render/render [:row "hello"])))))
+
+(deftest render-special-characters-test
+  (testing "renders unicode characters"
+    (is (= "✓" (render/render [:text "✓"])))
+    (is (= "⠋" (render/render [:text "⠋"])))
+    (is (= "🌑" (render/render [:text "🌑"])))
+    (is (= "╭──╮" (render/render [:row "╭" "──" "╮"]))))
+
+  (testing "renders newlines in text"
+    (is (= "a\nb" (render/render [:text "a\nb"])))))
+
+(deftest render-multiline-content-in-row-test
+  (testing "multiline elements in row"
+    (let [result (render/render [:row [:col "a" "b"] " " [:col "c" "d"]])]
+      (is (str/includes? result "a"))
+      (is (str/includes? result "b"))
+      (is (str/includes? result "c"))
+      (is (str/includes? result "d")))))
+
+(deftest render-deeply-nested-test
+  (testing "deeply nested structure"
+    (let [result (render/render
+                  [:col
+                   [:row
+                    [:col
+                     [:row
+                      [:text "deep"]]]]])]
+      (is (= "deep" result)))))
+
+(deftest render-box-edge-cases-test
+  (testing "box with empty content has corners and sides"
+    (let [result (render/render [:box ""])]
+      (is (str/includes? result "╭"))  ; Has corner
+      (is (str/includes? result "│"))))
+
+  (testing "box with very long content"
+    (let [long-text (apply str (repeat 100 "x"))
+          result (render/render [:box long-text])]
+      (is (str/includes? result long-text))))
+
+  (testing "box with multiline content"
+    (let [result (render/render [:box [:col "line1" "line2" "line3"]])]
+      (is (str/includes? result "line1"))
+      (is (str/includes? result "line2"))
+      (is (str/includes? result "line3"))))
+
+  (testing "box with all padding formats"
+    ;; Single value
+    (is (string? (render/render [:box {:padding 1} "x"])))
+    ;; Two values [v h]
+    (is (string? (render/render [:box {:padding [1 2]} "x"])))
+    ;; Four values [t r b l]
+    (is (string? (render/render [:box {:padding [1 2 3 4]} "x"])))
+    ;; Invalid (defaults to 0)
+    (is (string? (render/render [:box {:padding [1 2 3]} "x"])))))
+
+(deftest render-space-edge-cases-test
+  (testing "space with zero width"
+    (is (= "" (render/render [:space {:width 0}]))))
+
+  (testing "space with large dimensions"
+    (let [result (render/render [:space {:width 5 :height 3}])]
+      (is (= "     \n     \n     " result)))))
+
+(deftest render-gap-edge-cases-test
+  (testing "col with gap 0"
+    (is (= "a\nb" (render/render [:col {:gap 0} "a" "b"]))))
+
+  (testing "row with gap 0"
+    (is (= "ab" (render/render [:row {:gap 0} "a" "b"]))))
+
+  (testing "col with large gap"
+    (let [result (render/render [:col {:gap 3} "a" "b"])]
+      (is (= "a\n\n\n\nb" result))))
+
+  (testing "row with large gap"
+    (let [result (render/render [:row {:gap 5} "a" "b"])]
+      (is (= "a     b" result)))))
+
+(deftest render-styled-text-combinations-test
+  (testing "all style attributes combined"
+    (let [result (render/render [:text {:bold true
+                                        :dim true
+                                        :italic true
+                                        :underline true
+                                        :inverse true
+                                        :strike true
+                                        :fg :red
+                                        :bg :blue}
+                                 "styled"])]
+      (is (str/includes? result "styled"))
+      (is (str/includes? result "\u001b["))))
+
+  (testing "unknown fg color defaults gracefully"
+    (let [result (render/render [:text {:fg :nonexistent} "text"])]
+      (is (str/includes? result "text"))))
+
+  (testing "numeric values render as strings"
+    (is (= "42" (render/render 42)))
+    (is (= "3.14" (render/render 3.14)))
+    (is (= "-10" (render/render -10)))))
+
+;; =============================================================================
+;; KEY MATCHING EDGE CASES
+;; =============================================================================
+
+(deftest key-match-edge-cases-test
+  (testing "empty string pattern"
+    (is (not (input/key-match? [:key {:char \a}] ""))))
+
+  (testing "multi-char string pattern only matches first char"
+    ;; The current implementation only looks at first char
+    (is (input/key-match? [:key {:char \q}] "quit")))
+
+  (testing "nil message returns nil"
+    (is (nil? (input/key-match? nil "q")))
+    (is (nil? (input/key-match? nil :enter))))
+
+  (testing "non-key message returns nil"
+    (is (nil? (input/key-match? [:tick 123] "q")))
+    (is (nil? (input/key-match? [:http-success 200] :enter)))
+    (is (nil? (input/key-match? "not a vector" "q"))))
+
+  (testing "unknown key message structure"
+    (is (not (input/key-match? [:key {:unknown true}] "q")))
+    (is (not (input/key-match? [:key {}] "q")))))
+
+(deftest key-str-edge-cases-test
+  (testing "nil message returns nil"
+    (is (nil? (input/key->str nil))))
+
+  (testing "non-key message returns nil"
+    (is (nil? (input/key->str [:tick 123])))
+    (is (nil? (input/key->str [:custom :message]))))
+
+  (testing "key message with empty map"
+    (is (= "" (input/key->str [:key {}]))))
+
+  (testing "ctrl and alt combined"
+    ;; This is an edge case - both modifiers
+    (is (= "ctrl+alt+x" (input/key->str [:key {:ctrl true :alt true :char \x}])))))
+
+;; =============================================================================
+;; COMMAND EDGE CASES
+;; =============================================================================
+
+(deftest batch-edge-cases-test
+  (testing "batch with all nils"
+    (is (= [:batch] (tui/batch nil nil nil))))
+
+  (testing "batch with single command"
+    (is (= [:batch tui/quit] (tui/batch tui/quit))))
+
+  (testing "batch with no arguments"
+    (is (= [:batch] (tui/batch))))
+
+  (testing "batch with many commands"
+    (let [cmd (tui/batch (tui/tick 1) (tui/tick 2) (tui/tick 3) (tui/tick 4) (tui/tick 5))]
+      (is (= 6 (count cmd)))  ; :batch + 5 commands
+      (is (= :batch (first cmd))))))
+
+(deftest sequentially-edge-cases-test
+  (testing "sequentially with all nils"
+    (is (= [:seq] (tui/sequentially nil nil nil))))
+
+  (testing "sequentially with single command"
+    (is (= [:seq tui/quit] (tui/sequentially tui/quit))))
+
+  (testing "sequentially with no arguments"
+    (is (= [:seq] (tui/sequentially)))))
+
+(deftest tick-edge-cases-test
+  (testing "tick with zero"
+    (is (= [:tick 0] (tui/tick 0))))
+
+  (testing "tick with very large value"
+    (is (= [:tick 999999999] (tui/tick 999999999)))))
+
+(deftest send-msg-edge-cases-test
+  (testing "send-msg with nil"
+    (let [cmd (tui/send-msg nil)]
+      (is (fn? cmd))
+      (is (nil? (cmd)))))
+
+  (testing "send-msg with complex message"
+    (let [msg {:type :complex :data [1 2 3] :nested {:a :b}}
+          cmd (tui/send-msg msg)]
+      (is (= msg (cmd))))))
+
+;; =============================================================================
+;; ANSI EDGE CASES
+;; =============================================================================
+
+(deftest visible-length-edge-cases-test
+  (testing "empty string"
+    (is (= 0 (ansi/visible-length ""))))
+
+  (testing "only ANSI codes"
+    (is (= 0 (ansi/visible-length "\u001b[31m\u001b[0m"))))
+
+  (testing "multiple ANSI sequences"
+    (let [text (str (ansi/fg :red "a") (ansi/fg :blue "b") (ansi/fg :green "c"))]
+      (is (= 3 (ansi/visible-length text))))))
+
+(deftest pad-right-edge-cases-test
+  (testing "pad to width 0"
+    (is (= "hello" (ansi/pad-right "hello" 0))))
+
+  (testing "pad empty string"
+    (is (= "     " (ansi/pad-right "" 5))))
+
+  (testing "pad already wider"
+    (is (= "hello world" (ansi/pad-right "hello world" 5)))))
+
+(deftest pad-left-edge-cases-test
+  (testing "pad to width 0"
+    (is (= "hello" (ansi/pad-left "hello" 0))))
+
+  (testing "pad empty string"
+    (is (= "     " (ansi/pad-left "" 5)))))
+
+(deftest pad-center-edge-cases-test
+  (testing "center in width 0"
+    (is (= "hi" (ansi/pad-center "hi" 0))))
+
+  (testing "center empty string"
+    (is (= "   " (ansi/pad-center "" 3))))
+
+  (testing "center in exact width"
+    (is (= "hello" (ansi/pad-center "hello" 5)))))
+
+(deftest truncate-edge-cases-test
+  (testing "truncate to 0"
+    (is (= "…" (ansi/truncate "hello" 1))))
+
+  (testing "truncate empty string"
+    (is (= "" (ansi/truncate "" 5))))
+
+  (testing "truncate exact length"
+    (is (= "hello" (ansi/truncate "hello" 5)))))
+
+(deftest style-edge-cases-test
+  (testing "style with no attributes"
+    (is (= "text" (ansi/style "text"))))
+
+  (testing "style empty string"
+    (let [result (ansi/style "" :bold true)]
+      (is (str/includes? result ansi/reset)))))
+
+(deftest color-functions-edge-cases-test
+  (testing "fg with default color"
+    (let [result (ansi/fg :default "text")]
+      (is (str/includes? result "39m"))))
+
+  (testing "bg with default color"
+    (let [result (ansi/bg :default "text")]
+      (is (str/includes? result "49m"))))
+
+  (testing "256-color boundary values"
+    (is (string? (ansi/fg-256 0 "text")))
+    (is (string? (ansi/fg-256 255 "text"))))
+
+  (testing "RGB boundary values"
+    (is (string? (ansi/fg-rgb 0 0 0 "text")))
+    (is (string? (ansi/fg-rgb 255 255 255 "text")))))
+
+;; =============================================================================
+;; UPDATE FUNCTION EDGE CASES
+;; =============================================================================
+
+(deftest update-with-unknown-messages-test
+  (testing "update function handles unknown messages gracefully"
+    (let [update-fn (fn [model msg]
+                      (cond
+                        (tui/key= msg "q") [model tui/quit]
+                        :else [model nil]))]
+
+      ;; Unknown key
+      (let [[m cmd] (update-fn {:n 0} [:key {:char \x}])]
+        (is (= {:n 0} m))
+        (is (nil? cmd)))
+
+      ;; Unknown message type
+      (let [[m cmd] (update-fn {:n 0} [:unknown :message])]
+        (is (= {:n 0} m))
+        (is (nil? cmd)))
+
+      ;; Empty message
+      (let [[m cmd] (update-fn {:n 0} [])]
+        (is (= {:n 0} m))
+        (is (nil? cmd))))))
+
+(deftest model-with-complex-state-test
+  (testing "model with nested data structures"
+    (let [complex-model {:count 0
+                         :items ["a" "b" "c"]
+                         :nested {:deep {:value 42}}
+                         :selected #{}
+                         :history []}
+          update-fn (fn [model msg]
+                      (if (tui/key= msg :up)
+                        [(-> model
+                             (update :count inc)
+                             (update :history conj (:count model)))
+                         nil]
+                        [model nil]))]
+
+      (let [[m1 _] (update-fn complex-model [:key :up])
+            [m2 _] (update-fn m1 [:key :up])]
+        (is (= 1 (:count m1)))
+        (is (= [0] (:history m1)))
+        (is (= 2 (:count m2)))
+        (is (= [0 1] (:history m2)))
+        ;; Other fields unchanged
+        (is (= ["a" "b" "c"] (:items m2)))
+        (is (= 42 (get-in m2 [:nested :deep :value])))))))
+
+;; =============================================================================
+;; VIEW FUNCTION EDGE CASES
+;; =============================================================================
+
+(deftest view-with-conditional-rendering-test
+  (testing "view handles nil children gracefully"
+    (let [view (fn [show-extra]
+                 [:col
+                  [:text "always"]
+                  (when show-extra
+                    [:text "sometimes"])])]
+
+      (let [result1 (render/render (view true))
+            result2 (render/render (view false))]
+        (is (str/includes? result1 "always"))
+        (is (str/includes? result1 "sometimes"))
+        (is (str/includes? result2 "always"))
+        (is (not (str/includes? result2 "sometimes"))))))
+
+  (testing "view with for generating elements"
+    (let [view (fn [items]
+                 [:col
+                  (for [item items]
+                    [:text item])])]
+
+      (is (string? (render/render (view ["a" "b" "c"]))))
+      (is (string? (render/render (view [])))))))  ; Empty list
+
+(deftest view-with-dynamic-styles-test
+  (testing "dynamic style based on state"
+    (let [view (fn [{:keys [error loading success]}]
+                 [:text {:fg (cond
+                               error :red
+                               loading :yellow
+                               success :green
+                               :else :default)}
+                  (cond
+                    error "Error!"
+                    loading "Loading..."
+                    success "Done!"
+                    :else "Idle")])]
+
+      (is (str/includes? (render/render (view {:error true})) "Error!"))
+      (is (str/includes? (render/render (view {:loading true})) "Loading"))
+      (is (str/includes? (render/render (view {:success true})) "Done!"))
+      (is (str/includes? (render/render (view {})) "Idle")))))

test/tui/examples_test.clj

@@ -0,0 +1,612 @@
+(ns tui.examples-test
+  "Unit tests derived directly from example code patterns.
+   Tests update functions, view functions, and helper functions from examples."
+  (:require [clojure.test :refer [deftest testing is are]]
+            [clojure.string :as str]
+            [tui.core :as tui]
+            [tui.render :as render]))
+
+;; =============================================================================
+;; COUNTER EXAMPLE TESTS
+;; =============================================================================
+
+(deftest counter-initial-model-test
+  (testing "counter initial model structure"
+    (let [initial-model {:count 0}]
+      (is (= 0 (:count initial-model)))
+      (is (map? initial-model)))))
+
+(deftest counter-update-all-keys-test
+  (testing "counter responds to all documented keys"
+    (let [update-fn (fn [model msg]
+                      (cond
+                        (or (tui/key= msg "q")
+                            (tui/key= msg [:ctrl \c]))
+                        [model tui/quit]
+
+                        (or (tui/key= msg :up)
+                            (tui/key= msg "k"))
+                        [(update model :count inc) nil]
+
+                        (or (tui/key= msg :down)
+                            (tui/key= msg "j"))
+                        [(update model :count dec) nil]
+
+                        (tui/key= msg "r")
+                        [(assoc model :count 0) nil]
+
+                        :else
+                        [model nil]))]
+
+      ;; All increment keys
+      (are [msg] (= 1 (:count (first (update-fn {:count 0} msg))))
+        [:key :up]
+        [:key {:char \k}])
+
+      ;; All decrement keys
+      (are [msg] (= -1 (:count (first (update-fn {:count 0} msg))))
+        [:key :down]
+        [:key {:char \j}])
+
+      ;; All quit keys
+      (are [msg] (= tui/quit (second (update-fn {:count 0} msg)))
+        [:key {:char \q}]
+        [:key {:ctrl true :char \c}])
+
+      ;; Reset key
+      (is (= 0 (:count (first (update-fn {:count 42} [:key {:char \r}]))))))))
+
+(deftest counter-view-color-logic-test
+  (testing "counter view shows correct colors based on count"
+    (let [get-color (fn [count]
+                      (cond
+                        (pos? count) :green
+                        (neg? count) :red
+                        :else :default))]
+
+      (is (= :green (get-color 5)))
+      (is (= :green (get-color 1)))
+      (is (= :red (get-color -1)))
+      (is (= :red (get-color -100)))
+      (is (= :default (get-color 0))))))
+
+(deftest counter-view-structure-test
+  (testing "counter view produces valid hiccup"
+    (let [view (fn [{:keys [count]}]
+                 [:col {:gap 1}
+                  [:box {:border :rounded :padding [0 1]}
+                   [:col
+                    [:text {:bold true} "Counter"]
+                    [:text ""]
+                    [:text {:fg (cond
+                                  (pos? count) :green
+                                  (neg? count) :red
+                                  :else :default)}
+                     (str "Count: " count)]]]
+                  [:text {:fg :gray} "j/k or up/down: change value"]])]
+
+      ;; View returns valid hiccup
+      (let [result (view {:count 5})]
+        (is (vector? result))
+        (is (= :col (first result))))
+
+      ;; View renders without error
+      (is (string? (render/render (view {:count 5}))))
+      (is (string? (render/render (view {:count -3}))))
+      (is (string? (render/render (view {:count 0})))))))
+
+;; =============================================================================
+;; TIMER EXAMPLE TESTS
+;; =============================================================================
+
+(deftest timer-initial-model-test
+  (testing "timer initial model structure"
+    (let [initial-model {:seconds 10 :running true :done false}]
+      (is (= 10 (:seconds initial-model)))
+      (is (true? (:running initial-model)))
+      (is (false? (:done initial-model))))))
+
+(deftest timer-format-time-test
+  (testing "format-time produces MM:SS format"
+    (let [format-time (fn [seconds]
+                        (let [mins (quot seconds 60)
+                              secs (mod seconds 60)]
+                          (format "%02d:%02d" mins secs)))]
+
+      (is (= "00:00" (format-time 0)))
+      (is (= "00:01" (format-time 1)))
+      (is (= "00:10" (format-time 10)))
+      (is (= "00:59" (format-time 59)))
+      (is (= "01:00" (format-time 60)))
+      (is (= "01:30" (format-time 90)))
+      (is (= "05:00" (format-time 300)))
+      (is (= "10:00" (format-time 600)))
+      (is (= "59:59" (format-time 3599))))))
+
+(deftest timer-tick-countdown-test
+  (testing "timer tick decrements and reaches zero"
+    (let [update-fn (fn [{:keys [seconds running] :as model} msg]
+                      (cond
+                        (= (first msg) :tick)
+                        (if running
+                          (let [new-seconds (dec seconds)]
+                            (if (<= new-seconds 0)
+                              [(assoc model :seconds 0 :done true :running false) nil]
+                              [(assoc model :seconds new-seconds) (tui/tick 1000)]))
+                          [model nil])
+                        :else [model nil]))]
+
+      ;; Normal tick
+      (let [[m1 c1] (update-fn {:seconds 10 :running true :done false} [:tick 123])]
+        (is (= 9 (:seconds m1)))
+        (is (= [:tick 1000] c1)))
+
+      ;; Tick to zero
+      (let [[m1 c1] (update-fn {:seconds 1 :running true :done false} [:tick 123])]
+        (is (= 0 (:seconds m1)))
+        (is (true? (:done m1)))
+        (is (false? (:running m1)))
+        (is (nil? c1)))
+
+      ;; Tick when paused does nothing
+      (let [[m1 c1] (update-fn {:seconds 5 :running false :done false} [:tick 123])]
+        (is (= 5 (:seconds m1)))
+        (is (nil? c1))))))
+
+(deftest timer-pause-resume-test
+  (testing "timer pause/resume with space key"
+    (let [update-fn (fn [{:keys [running] :as model} msg]
+                      (if (tui/key= msg " ")
+                        (let [new-running (not running)]
+                          [(assoc model :running new-running)
+                           (when new-running (tui/tick 1000))])
+                        [model nil]))]
+
+      ;; Pause (running -> not running)
+      (let [[m1 c1] (update-fn {:seconds 5 :running true} [:key {:char \space}])]
+        (is (false? (:running m1)))
+        (is (nil? c1)))
+
+      ;; Resume (not running -> running)
+      (let [[m1 c1] (update-fn {:seconds 5 :running false} [:key {:char \space}])]
+        (is (true? (:running m1)))
+        (is (= [:tick 1000] c1))))))
+
+(deftest timer-reset-test
+  (testing "timer reset restores initial state"
+    (let [update-fn (fn [model msg]
+                      (if (tui/key= msg "r")
+                        [(assoc model :seconds 10 :done false :running true)
+                         (tui/tick 1000)]
+                        [model nil]))]
+
+      (let [[m1 c1] (update-fn {:seconds 0 :done true :running false} [:key {:char \r}])]
+        (is (= 10 (:seconds m1)))
+        (is (false? (:done m1)))
+        (is (true? (:running m1)))
+        (is (= [:tick 1000] c1))))))
+
+(deftest timer-view-color-logic-test
+  (testing "timer view shows correct colors"
+    (let [get-color (fn [done seconds]
+                      (cond
+                        done :green
+                        (< seconds 5) :red
+                        :else :cyan))]
+
+      (is (= :green (get-color true 0)))
+      (is (= :red (get-color false 4)))
+      (is (= :red (get-color false 1)))
+      (is (= :cyan (get-color false 5)))
+      (is (= :cyan (get-color false 10))))))
+
+;; =============================================================================
+;; SPINNER EXAMPLE TESTS
+;; =============================================================================
+
+(def spinner-styles
+  {:dots     ["⠋" "⠙" "⠹" "⠸" "⠼" "⠴" "⠦" "⠧" "⠇" "⠏"]
+   :line     ["|" "/" "-" "\\"]
+   :circle   ["◐" "◓" "◑" "◒"]
+   :square   ["◰" "◳" "◲" "◱"]
+   :triangle ["◢" "◣" "◤" "◥"]
+   :bounce   ["⠁" "⠂" "⠄" "⠂"]
+   :dots2    ["⣾" "⣽" "⣻" "⢿" "⡿" "⣟" "⣯" "⣷"]
+   :arc      ["◜" "◠" "◝" "◞" "◡" "◟"]
+   :moon     ["🌑" "🌒" "🌓" "🌔" "🌕" "🌖" "🌗" "🌘"]})
+
+(deftest spinner-frame-cycling-test
+  (testing "spinner frame cycles through all frames"
+    (let [spinner-view (fn [frame style]
+                         (let [frames (get spinner-styles style)
+                               idx (mod frame (count frames))]
+                           (nth frames idx)))]
+
+      ;; Dots style has 10 frames
+      (is (= "⠋" (spinner-view 0 :dots)))
+      (is (= "⠙" (spinner-view 1 :dots)))
+      (is (= "⠋" (spinner-view 10 :dots)))  ; Wraps around
+      (is (= "⠙" (spinner-view 11 :dots)))
+
+      ;; Line style has 4 frames
+      (is (= "|" (spinner-view 0 :line)))
+      (is (= "/" (spinner-view 1 :line)))
+      (is (= "|" (spinner-view 4 :line)))  ; Wraps around
+
+      ;; Circle style
+      (is (= "◐" (spinner-view 0 :circle)))
+      (is (= "◐" (spinner-view 4 :circle))))))  ; Wraps around after 4 frames
+
+(deftest spinner-tick-advances-frame-test
+  (testing "spinner tick advances frame when loading"
+    (let [update-fn (fn [model msg]
+                      (if (= (first msg) :tick)
+                        (if (:loading model)
+                          [(update model :frame inc) (tui/tick 80)]
+                          [model nil])
+                        [model nil]))]
+
+      ;; Tick advances frame when loading
+      (let [[m1 c1] (update-fn {:frame 0 :loading true} [:tick 123])]
+        (is (= 1 (:frame m1)))
+        (is (= [:tick 80] c1)))
+
+      ;; Tick does nothing when not loading
+      (let [[m1 c1] (update-fn {:frame 5 :loading false} [:tick 123])]
+        (is (= 5 (:frame m1)))
+        (is (nil? c1))))))
+
+(deftest spinner-style-switching-test
+  (testing "spinner tab key cycles through styles"
+    (let [styles (keys spinner-styles)
+          update-fn (fn [{:keys [style-idx] :as model} msg]
+                      (if (tui/key= msg :tab)
+                        (let [new-idx (mod (inc style-idx) (count styles))]
+                          [(assoc model
+                                  :style-idx new-idx
+                                  :style (nth styles new-idx))
+                           nil])
+                        [model nil]))]
+
+      ;; Tab advances style
+      (let [[m1 _] (update-fn {:style-idx 0 :style (first styles)} [:key :tab])]
+        (is (= 1 (:style-idx m1))))
+
+      ;; Tab wraps around
+      (let [last-idx (dec (count styles))
+            [m1 _] (update-fn {:style-idx last-idx :style (last styles)} [:key :tab])]
+        (is (= 0 (:style-idx m1)))))))
+
+(deftest spinner-completion-test
+  (testing "spinner space key completes loading"
+    (let [update-fn (fn [model msg]
+                      (if (tui/key= msg " ")
+                        [(assoc model :loading false :message "Done!") nil]
+                        [model nil]))]
+
+      (let [[m1 _] (update-fn {:loading true :message "Loading..."} [:key {:char \space}])]
+        (is (false? (:loading m1)))
+        (is (= "Done!" (:message m1)))))))
+
+(deftest spinner-restart-test
+  (testing "spinner r key restarts animation"
+    (let [update-fn (fn [model msg]
+                      (if (tui/key= msg "r")
+                        [(assoc model :loading true :frame 0 :message "Loading...")
+                         (tui/tick 80)]
+                        [model nil]))]
+
+      (let [[m1 c1] (update-fn {:loading false :frame 100 :message "Done!"} [:key {:char \r}])]
+        (is (true? (:loading m1)))
+        (is (= 0 (:frame m1)))
+        (is (= "Loading..." (:message m1)))
+        (is (= [:tick 80] c1))))))
+
+;; =============================================================================
+;; LIST SELECTION EXAMPLE TESTS
+;; =============================================================================
+
+(deftest list-selection-initial-model-test
+  (testing "list selection initial model structure"
+    (let [initial-model {:cursor 0
+                         :items ["Pizza" "Sushi" "Tacos" "Burger" "Pasta"]
+                         :selected #{}
+                         :submitted false}]
+      (is (= 0 (:cursor initial-model)))
+      (is (= 5 (count (:items initial-model))))
+      (is (empty? (:selected initial-model)))
+      (is (false? (:submitted initial-model))))))
+
+(deftest list-selection-cursor-navigation-test
+  (testing "cursor navigation respects bounds"
+    (let [items ["A" "B" "C" "D" "E"]
+          update-fn (fn [{:keys [cursor] :as model} msg]
+                      (cond
+                        (or (tui/key= msg :up)
+                            (tui/key= msg "k"))
+                        [(update model :cursor #(max 0 (dec %))) nil]
+
+                        (or (tui/key= msg :down)
+                            (tui/key= msg "j"))
+                        [(update model :cursor #(min (dec (count items)) (inc %))) nil]
+
+                        :else [model nil]))]
+
+      ;; Move down through list
+      (let [m0 {:cursor 0}
+            [m1 _] (update-fn m0 [:key :down])
+            [m2 _] (update-fn m1 [:key :down])
+            [m3 _] (update-fn m2 [:key :down])
+            [m4 _] (update-fn m3 [:key :down])
+            [m5 _] (update-fn m4 [:key :down])]  ; Should stop at 4
+        (is (= 1 (:cursor m1)))
+        (is (= 2 (:cursor m2)))
+        (is (= 3 (:cursor m3)))
+        (is (= 4 (:cursor m4)))
+        (is (= 4 (:cursor m5))))  ; Clamped at max
+
+      ;; Move up from top
+      (let [[m1 _] (update-fn {:cursor 0} [:key :up])]
+        (is (= 0 (:cursor m1)))))))  ; Clamped at 0
+
+(deftest list-selection-toggle-test
+  (testing "space toggles selection"
+    (let [update-fn (fn [{:keys [cursor] :as model} msg]
+                      (if (tui/key= msg " ")
+                        [(update model :selected
+                                 #(if (contains? % cursor)
+                                    (disj % cursor)
+                                    (conj % cursor)))
+                         nil]
+                        [model nil]))]
+
+      ;; Select item
+      (let [[m1 _] (update-fn {:cursor 0 :selected #{}} [:key {:char \space}])]
+        (is (= #{0} (:selected m1))))
+
+      ;; Select multiple items
+      (let [m0 {:cursor 0 :selected #{}}
+            [m1 _] (update-fn m0 [:key {:char \space}])
+            m1' (assoc m1 :cursor 2)
+            [m2 _] (update-fn m1' [:key {:char \space}])
+            m2' (assoc m2 :cursor 4)
+            [m3 _] (update-fn m2' [:key {:char \space}])]
+        (is (= #{0 2 4} (:selected m3))))
+
+      ;; Deselect item
+      (let [[m1 _] (update-fn {:cursor 1 :selected #{1 2}} [:key {:char \space}])]
+        (is (= #{2} (:selected m1)))))))
+
+(deftest list-selection-submit-test
+  (testing "enter submits selection"
+    (let [update-fn (fn [model msg]
+                      (if (tui/key= msg :enter)
+                        [(assoc model :submitted true) tui/quit]
+                        [model nil]))]
+
+      (let [[m1 c1] (update-fn {:selected #{0 2} :submitted false} [:key :enter])]
+        (is (true? (:submitted m1)))
+        (is (= tui/quit c1))))))
+
+(deftest list-selection-view-item-count-test
+  (testing "view shows correct item count"
+    (let [item-count-text (fn [n]
+                            (str n " item" (when (not= 1 n) "s") " selected"))]
+
+      (is (= "0 items selected" (item-count-text 0)))
+      (is (= "1 item selected" (item-count-text 1)))
+      (is (= "2 items selected" (item-count-text 2)))
+      (is (= "5 items selected" (item-count-text 5))))))
+
+;; =============================================================================
+;; VIEWS EXAMPLE TESTS
+;; =============================================================================
+
+(deftest views-initial-model-test
+  (testing "views initial model structure"
+    (let [initial-model {:view :menu
+                         :cursor 0
+                         :items [{:name "Profile" :desc "Profile settings"}
+                                 {:name "Settings" :desc "App preferences"}]
+                         :selected nil}]
+      (is (= :menu (:view initial-model)))
+      (is (= 0 (:cursor initial-model)))
+      (is (nil? (:selected initial-model))))))
+
+(deftest views-menu-navigation-test
+  (testing "menu view cursor navigation"
+    (let [items [{:name "A"} {:name "B"} {:name "C"} {:name "D"}]
+          update-fn (fn [{:keys [cursor] :as model} msg]
+                      (cond
+                        (or (tui/key= msg :up)
+                            (tui/key= msg "k"))
+                        [(update model :cursor #(max 0 (dec %))) nil]
+
+                        (or (tui/key= msg :down)
+                            (tui/key= msg "j"))
+                        [(update model :cursor #(min (dec (count items)) (inc %))) nil]
+
+                        :else [model nil]))]
+
+      ;; Navigate down
+      (let [[m1 _] (update-fn {:cursor 0} [:key {:char \j}])]
+        (is (= 1 (:cursor m1))))
+
+      ;; Navigate up
+      (let [[m1 _] (update-fn {:cursor 2} [:key {:char \k}])]
+        (is (= 1 (:cursor m1)))))))
+
+(deftest views-state-transitions-test
+  (testing "all view state transitions"
+    (let [items [{:name "Profile"} {:name "Settings"}]
+          update-fn (fn [{:keys [view cursor] :as model} msg]
+                      (case view
+                        :menu
+                        (cond
+                          (tui/key= msg :enter)
+                          [(assoc model :view :detail :selected (nth items cursor)) nil]
+                          (tui/key= msg "q")
+                          [model tui/quit]
+                          :else [model nil])
+
+                        :detail
+                        (cond
+                          (or (tui/key= msg :escape)
+                              (tui/key= msg "b"))
+                          [(assoc model :view :menu :selected nil) nil]
+                          (tui/key= msg "q")
+                          [(assoc model :view :confirm) nil]
+                          :else [model nil])
+
+                        :confirm
+                        (cond
+                          (tui/key= msg "y")
+                          [model tui/quit]
+                          (or (tui/key= msg "n")
+                              (tui/key= msg :escape))
+                          [(assoc model :view :detail) nil]
+                          :else [model nil])))]
+
+      ;; Menu -> Detail via enter
+      (let [[m1 _] (update-fn {:view :menu :cursor 0 :items items} [:key :enter])]
+        (is (= :detail (:view m1)))
+        (is (= "Profile" (:name (:selected m1)))))
+
+      ;; Detail -> Menu via escape
+      (let [[m1 _] (update-fn {:view :detail :selected {:name "X"}} [:key :escape])]
+        (is (= :menu (:view m1)))
+        (is (nil? (:selected m1))))
+
+      ;; Detail -> Menu via b
+      (let [[m1 _] (update-fn {:view :detail :selected {:name "X"}} [:key {:char \b}])]
+        (is (= :menu (:view m1))))
+
+      ;; Detail -> Confirm via q
+      (let [[m1 _] (update-fn {:view :detail} [:key {:char \q}])]
+        (is (= :confirm (:view m1))))
+
+      ;; Confirm -> Quit via y
+      (let [[_ c1] (update-fn {:view :confirm} [:key {:char \y}])]
+        (is (= tui/quit c1)))
+
+      ;; Confirm -> Detail via n
+      (let [[m1 _] (update-fn {:view :confirm} [:key {:char \n}])]
+        (is (= :detail (:view m1))))
+
+      ;; Confirm -> Detail via escape
+      (let [[m1 _] (update-fn {:view :confirm} [:key :escape])]
+        (is (= :detail (:view m1)))))))
+
+;; =============================================================================
+;; HTTP EXAMPLE TESTS
+;; =============================================================================
+
+(deftest http-initial-model-test
+  (testing "http initial model structure"
+    (let [initial-model {:state :idle
+                         :status nil
+                         :error nil
+                         :url "https://httpstat.us/200"}]
+      (is (= :idle (:state initial-model)))
+      (is (nil? (:status initial-model)))
+      (is (nil? (:error initial-model)))
+      (is (string? (:url initial-model))))))
+
+(deftest http-state-machine-test
+  (testing "http state transitions"
+    (let [update-fn (fn [{:keys [state url] :as model} msg]
+                      (cond
+                        ;; Start request
+                        (and (= state :idle)
+                             (tui/key= msg :enter))
+                        [(assoc model :state :loading)
+                         (fn [] [:http-success 200])]
+
+                        ;; Reset
+                        (tui/key= msg "r")
+                        [(assoc model :state :idle :status nil :error nil) nil]
+
+                        ;; HTTP success
+                        (= (first msg) :http-success)
+                        [(assoc model :state :success :status (second msg)) nil]
+
+                        ;; HTTP error
+                        (= (first msg) :http-error)
+                        [(assoc model :state :error :error (second msg)) nil]
+
+                        :else
+                        [model nil]))]
+
+      ;; Idle -> Loading via enter
+      (let [[m1 c1] (update-fn {:state :idle :url "http://test.com"} [:key :enter])]
+        (is (= :loading (:state m1)))
+        (is (fn? c1)))
+
+      ;; Enter ignored when not idle
+      (let [[m1 c1] (update-fn {:state :loading} [:key :enter])]
+        (is (= :loading (:state m1)))
+        (is (nil? c1)))
+
+      ;; Loading -> Success
+      (let [[m1 _] (update-fn {:state :loading} [:http-success 200])]
+        (is (= :success (:state m1)))
+        (is (= 200 (:status m1))))
+
+      ;; Loading -> Error
+      (let [[m1 _] (update-fn {:state :loading} [:http-error "Connection refused"])]
+        (is (= :error (:state m1)))
+        (is (= "Connection refused" (:error m1))))
+
+      ;; Reset from any state
+      (doseq [state [:idle :loading :success :error]]
+        (let [[m1 _] (update-fn {:state state :status 200 :error "err"} [:key {:char \r}])]
+          (is (= :idle (:state m1)))
+          (is (nil? (:status m1)))
+          (is (nil? (:error m1))))))))
+
+(deftest http-fetch-command-test
+  (testing "fetch command creates async function"
+    (let [fetch-url (fn [url]
+                      (fn []
+                        ;; Simulate success
+                        [:http-success 200]))]
+
+      (let [cmd (fetch-url "https://test.com")]
+        (is (fn? cmd))
+        (is (= [:http-success 200] (cmd)))))))
+
+(deftest http-view-states-test
+  (testing "http view renders different states"
+    (let [render-state (fn [state status error]
+                         (case state
+                           :idle [:text {:fg :gray} "Press enter to fetch..."]
+                           :loading [:row {:gap 1}
+                                     [:text {:fg :yellow} "⠋"]
+                                     [:text "Fetching..."]]
+                           :success [:row {:gap 1}
+                                     [:text {:fg :green} "✓"]
+                                     [:text (str "Status: " status)]]
+                           :error [:col
+                                   [:row {:gap 1}
+                                    [:text {:fg :red} "✗"]
+                                    [:text {:fg :red} "Error:"]]
+                                   [:text {:fg :red} error]]))]
+
+      ;; Idle state
+      (let [view (render-state :idle nil nil)]
+        (is (= :text (first view)))
+        (is (str/includes? (render/render view) "Press enter")))
+
+      ;; Loading state
+      (let [view (render-state :loading nil nil)]
+        (is (= :row (first view)))
+        (is (str/includes? (render/render view) "Fetching")))
+
+      ;; Success state
+      (let [view (render-state :success 200 nil)]
+        (is (str/includes? (render/render view) "Status: 200")))
+
+      ;; Error state
+      (let [view (render-state :error nil "Connection refused")]
+        (is (str/includes? (render/render view) "Error"))
+        (is (str/includes? (render/render view) "Connection refused"))))))

test/tui/input_test.clj

@@ -0,0 +1,94 @@
+(ns tui.input-test
+  "Unit tests for input parsing and key matching."
+  (:require [clojure.test :refer [deftest testing is]]
+            [tui.input :as input]))
+
+;; === Key Matching Tests ===
+
+(deftest key-match-character-test
+  (testing "matches single character keys"
+    (is (input/key-match? [:key {:char \q}] "q"))
+    (is (input/key-match? [:key {:char \a}] "a"))
+    (is (input/key-match? [:key {:char \1}] "1")))
+
+  (testing "does not match different characters"
+    (is (not (input/key-match? [:key {:char \q}] "a")))
+    (is (not (input/key-match? [:key {:char \x}] "y"))))
+
+  (testing "does not match ctrl+char as plain char"
+    (is (not (input/key-match? [:key {:ctrl true :char \c}] "c"))))
+
+  (testing "does not match alt+char as plain char"
+    (is (not (input/key-match? [:key {:alt true :char \x}] "x")))))
+
+(deftest key-match-special-keys-test
+  (testing "matches special keys by keyword"
+    (is (input/key-match? [:key :enter] :enter))
+    (is (input/key-match? [:key :escape] :escape))
+    (is (input/key-match? [:key :backspace] :backspace))
+    (is (input/key-match? [:key :tab] :tab)))
+
+  (testing "matches arrow keys"
+    (is (input/key-match? [:key :up] :up))
+    (is (input/key-match? [:key :down] :down))
+    (is (input/key-match? [:key :left] :left))
+    (is (input/key-match? [:key :right] :right)))
+
+  (testing "matches function keys"
+    (is (input/key-match? [:key :f1] :f1))
+    (is (input/key-match? [:key :f12] :f12)))
+
+  (testing "does not match wrong special keys"
+    (is (not (input/key-match? [:key :up] :down)))
+    (is (not (input/key-match? [:key :enter] :escape)))))
+
+(deftest key-match-ctrl-combo-test
+  (testing "matches ctrl+char combinations"
+    (is (input/key-match? [:key {:ctrl true :char \c}] [:ctrl \c]))
+    (is (input/key-match? [:key {:ctrl true :char \x}] [:ctrl \x]))
+    (is (input/key-match? [:key {:ctrl true :char \z}] [:ctrl \z])))
+
+  (testing "does not match wrong ctrl combinations"
+    (is (not (input/key-match? [:key {:ctrl true :char \c}] [:ctrl \x])))
+    (is (not (input/key-match? [:key {:char \c}] [:ctrl \c])))))
+
+(deftest key-match-alt-combo-test
+  (testing "matches alt+char combinations"
+    (is (input/key-match? [:key {:alt true :char \x}] [:alt \x]))
+    (is (input/key-match? [:key {:alt true :char \a}] [:alt \a])))
+
+  (testing "does not match wrong alt combinations"
+    (is (not (input/key-match? [:key {:alt true :char \x}] [:alt \y])))
+    (is (not (input/key-match? [:key {:char \x}] [:alt \x])))))
+
+(deftest key-match-non-key-messages-test
+  (testing "returns nil for non-key messages"
+    (is (nil? (input/key-match? [:tick 123] "q")))
+    (is (nil? (input/key-match? [:quit] :enter)))
+    (is (nil? (input/key-match? nil "a")))))
+
+;; === Key to String Tests ===
+
+(deftest key->str-special-keys-test
+  (testing "converts special keys to strings"
+    (is (= "enter" (input/key->str [:key :enter])))
+    (is (= "escape" (input/key->str [:key :escape])))
+    (is (= "up" (input/key->str [:key :up])))
+    (is (= "f1" (input/key->str [:key :f1])))))
+
+(deftest key->str-character-keys-test
+  (testing "converts character keys to strings"
+    (is (= "q" (input/key->str [:key {:char \q}])))
+    (is (= "a" (input/key->str [:key {:char \a}])))))
+
+(deftest key->str-modifier-keys-test
+  (testing "converts ctrl combinations to strings"
+    (is (= "ctrl+c" (input/key->str [:key {:ctrl true :char \c}]))))
+
+  (testing "converts alt combinations to strings"
+    (is (= "alt+x" (input/key->str [:key {:alt true :char \x}])))))
+
+(deftest key->str-non-key-messages-test
+  (testing "returns nil for non-key messages"
+    (is (nil? (input/key->str [:tick 123])))
+    (is (nil? (input/key->str nil)))))

test/tui/render_test.clj

@@ -0,0 +1,156 @@
+(ns tui.render-test
+  "Unit tests for hiccup rendering."
+  (:require [clojure.test :refer [deftest testing is]]
+            [clojure.string :as str]
+            [tui.render :as render]
+            [tui.ansi :as ansi]))
+
+;; === Text Rendering Tests ===
+
+(deftest render-plain-text-test
+  (testing "renders plain strings"
+    (is (= "hello" (render/render "hello")))
+    (is (= "world" (render/render "world"))))
+
+  (testing "renders numbers as strings"
+    (is (= "42" (render/render 42)))
+    (is (= "3.14" (render/render 3.14))))
+
+  (testing "renders nil as empty string"
+    (is (= "" (render/render nil)))))
+
+(deftest render-text-element-test
+  (testing "renders :text element with string child"
+    (is (= "hello" (render/render [:text "hello"]))))
+
+  (testing "renders :text element with multiple children"
+    (is (= "hello world" (render/render [:text "hello" " " "world"]))))
+
+  (testing "renders nested text"
+    (is (= "42" (render/render [:text 42])))))
+
+(deftest render-styled-text-test
+  (testing "renders bold text"
+    (let [result (render/render [:text {:bold true} "bold"])]
+      (is (str/includes? result "bold"))
+      (is (str/includes? result "\u001b["))  ; Contains ANSI escape
+      (is (str/includes? result "1m"))))     ; Bold code
+
+  (testing "renders colored text"
+    (let [result (render/render [:text {:fg :red} "red"])]
+      (is (str/includes? result "red"))
+      (is (str/includes? result "31m"))))    ; Red foreground code
+
+  (testing "renders multiple styles"
+    (let [result (render/render [:text {:bold true :fg :green} "styled"])]
+      (is (str/includes? result "styled"))
+      (is (str/includes? result "1"))        ; Bold
+      (is (str/includes? result "32")))))    ; Green
+
+;; === Layout Tests ===
+
+(deftest render-row-test
+  (testing "renders row with children horizontally"
+    (is (= "ab" (render/render [:row "a" "b"])))
+    (is (= "abc" (render/render [:row "a" "b" "c"]))))
+
+  (testing "renders row with gap"
+    (is (= "a b" (render/render [:row {:gap 1} "a" "b"])))
+    (is (= "a  b" (render/render [:row {:gap 2} "a" "b"]))))
+
+  (testing "renders nested elements in row"
+    (is (= "hello world" (render/render [:row [:text "hello"] " " [:text "world"]])))))
+
+(deftest render-col-test
+  (testing "renders col with children vertically"
+    (is (= "a\nb" (render/render [:col "a" "b"])))
+    (is (= "a\nb\nc" (render/render [:col "a" "b" "c"]))))
+
+  (testing "renders col with gap"
+    (is (= "a\n\nb" (render/render [:col {:gap 1} "a" "b"])))
+    (is (= "a\n\n\nb" (render/render [:col {:gap 2} "a" "b"]))))
+
+  (testing "renders nested elements in col"
+    (is (= "line1\nline2" (render/render [:col [:text "line1"] [:text "line2"]])))))
+
+(deftest render-nested-layout-test
+  (testing "renders row inside col"
+    (is (= "a b\nc d" (render/render [:col
+                                       [:row "a" " " "b"]
+                                       [:row "c" " " "d"]]))))
+
+  (testing "renders col inside row"
+    (is (= "a\nb c\nd" (render/render [:row
+                                        [:col "a" "b"]
+                                        " "
+                                        [:col "c" "d"]])))))
+
+;; === Box Tests ===
+
+(deftest render-box-test
+  (testing "renders box with content"
+    (let [result (render/render [:box "hello"])]
+      (is (str/includes? result "hello"))
+      (is (str/includes? result "─"))        ; Horizontal border
+      (is (str/includes? result "│"))))      ; Vertical border
+
+  (testing "renders box with title"
+    (let [result (render/render [:box {:title "Title"} "content"])]
+      (is (str/includes? result "Title"))
+      (is (str/includes? result "content"))))
+
+  (testing "renders box with different border styles"
+    (let [rounded (render/render [:box {:border :rounded} "x"])
+          single (render/render [:box {:border :single} "x"])
+          double (render/render [:box {:border :double} "x"])
+          ascii (render/render [:box {:border :ascii} "x"])]
+      (is (str/includes? rounded "╭"))
+      (is (str/includes? single "┌"))
+      (is (str/includes? double "╔"))
+      (is (str/includes? ascii "+")))))
+
+(deftest render-box-padding-test
+  (testing "renders box with numeric padding"
+    (let [result (render/render [:box {:padding 1} "x"])
+          lines (str/split result #"\n")]
+      ;; Should have empty lines for vertical padding
+      (is (> (count lines) 3))))
+
+  (testing "renders box with vector padding"
+    (let [result (render/render [:box {:padding [0 2]} "x"])]
+      ;; Should have horizontal padding (spaces around content)
+      (is (str/includes? result "  x  ")))))
+
+;; === Space Tests ===
+
+(deftest render-space-test
+  (testing "renders space with default size"
+    (is (= " " (render/render [:space]))))
+
+  (testing "renders space with custom width"
+    (is (= "   " (render/render [:space {:width 3}]))))
+
+  (testing "renders space with custom height"
+    (is (= " \n " (render/render [:space {:height 2}]))))
+
+  (testing "renders space with width and height"
+    (is (= "  \n  " (render/render [:space {:width 2 :height 2}])))))
+
+;; === Convenience Function Tests ===
+
+(deftest convenience-functions-test
+  (testing "text function creates text element"
+    (is (= [:text {} "hello"] (render/text "hello")))
+    (is (= [:text {:bold true} "bold"] (render/text {:bold true} "bold"))))
+
+  (testing "row function creates row element"
+    (is (= [:row {} "a" "b"] (render/row "a" "b")))
+    (is (= [:row {:gap 1} "a" "b"] (render/row {:gap 1} "a" "b"))))
+
+  (testing "col function creates col element"
+    (is (= [:col {} "a" "b"] (render/col "a" "b")))
+    (is (= [:col {:gap 1} "a" "b"] (render/col {:gap 1} "a" "b"))))
+
+  (testing "box function creates box element"
+    (is (= [:box {} "content"] (render/box "content")))
+    (is (= [:box {:border :single} "x"] (render/box {:border :single} "x")))))

test/tui/simple_test.clj

@@ -0,0 +1,281 @@
+(ns tui.simple-test
+  "Unit tests for the simple (synchronous) TUI runtime."
+  (:require [clojure.test :refer [deftest testing is]]
+            [tui.simple :as simple]
+            [tui.render :as render]))
+
+;; =============================================================================
+;; QUIT COMMAND TESTS
+;; =============================================================================
+
+(deftest quit-command-test
+  (testing "quit command is correct vector"
+    (is (= [:quit] simple/quit))
+    (is (vector? simple/quit))
+    (is (= :quit (first simple/quit)))))
+
+;; =============================================================================
+;; KEY MATCHING TESTS (same API as tui.core)
+;; =============================================================================
+
+(deftest key=-character-keys-test
+  (testing "matches single character keys"
+    (is (simple/key= [:key {:char \q}] "q"))
+    (is (simple/key= [:key {:char \a}] "a"))
+    (is (simple/key= [:key {:char \space}] " ")))
+
+  (testing "does not match different characters"
+    (is (not (simple/key= [:key {:char \q}] "a")))
+    (is (not (simple/key= [:key {:char \x}] "y")))))
+
+(deftest key=-special-keys-test
+  (testing "matches special keys by keyword"
+    (is (simple/key= [:key :enter] :enter))
+    (is (simple/key= [:key :escape] :escape))
+    (is (simple/key= [:key :up] :up))
+    (is (simple/key= [:key :down] :down))
+    (is (simple/key= [:key :left] :left))
+    (is (simple/key= [:key :right] :right))
+    (is (simple/key= [:key :tab] :tab))
+    (is (simple/key= [:key :backspace] :backspace))))
+
+(deftest key=-ctrl-combos-test
+  (testing "matches ctrl+char combinations"
+    (is (simple/key= [:key {:ctrl true :char \c}] [:ctrl \c]))
+    (is (simple/key= [:key {:ctrl true :char \x}] [:ctrl \x])))
+
+  (testing "ctrl combo does not match plain char"
+    (is (not (simple/key= [:key {:ctrl true :char \c}] "c")))
+    (is (not (simple/key= [:key {:char \c}] [:ctrl \c])))))
+
+(deftest key=-alt-combos-test
+  (testing "matches alt+char combinations"
+    (is (simple/key= [:key {:alt true :char \x}] [:alt \x])))
+
+  (testing "alt combo does not match plain char"
+    (is (not (simple/key= [:key {:alt true :char \x}] "x")))))
+
+(deftest key=-non-key-messages-test
+  (testing "returns nil for non-key messages"
+    (is (nil? (simple/key= [:tick 123] "q")))
+    (is (nil? (simple/key= [:quit] :enter)))
+    (is (nil? (simple/key= nil "a")))))
+
+;; =============================================================================
+;; KEY-STR TESTS
+;; =============================================================================
+
+(deftest key-str-test
+  (testing "converts character keys to strings"
+    (is (= "q" (simple/key-str [:key {:char \q}])))
+    (is (= " " (simple/key-str [:key {:char \space}]))))
+
+  (testing "converts special keys to strings"
+    (is (= "enter" (simple/key-str [:key :enter])))
+    (is (= "escape" (simple/key-str [:key :escape])))
+    (is (= "up" (simple/key-str [:key :up]))))
+
+  (testing "converts modifier keys to strings"
+    (is (= "ctrl+c" (simple/key-str [:key {:ctrl true :char \c}])))
+    (is (= "alt+x" (simple/key-str [:key {:alt true :char \x}]))))
+
+  (testing "returns nil for non-key messages"
+    (is (nil? (simple/key-str [:tick 123])))
+    (is (nil? (simple/key-str nil)))))
+
+;; =============================================================================
+;; RENDER RE-EXPORT TESTS
+;; =============================================================================
+
+(deftest render-reexport-test
+  (testing "simple/render is the same as render/render"
+    (is (= (render/render [:text "hello"])
+           (simple/render [:text "hello"])))
+    (is (= (render/render [:col "a" "b"])
+           (simple/render [:col "a" "b"])))))
+
+;; =============================================================================
+;; UPDATE FUNCTION CONTRACT TESTS (same as tui.core)
+;; =============================================================================
+
+(deftest simple-update-contract-test
+  (testing "update function returns [model cmd] tuple"
+    (let [update-fn (fn [model msg]
+                      (cond
+                        (simple/key= msg "q") [model simple/quit]
+                        (simple/key= msg :up) [(update model :n inc) nil]
+                        :else [model nil]))
+          model {:n 0}]
+
+      ;; Quit returns command
+      (let [[new-model cmd] (update-fn model [:key {:char \q}])]
+        (is (= model new-model))
+        (is (= [:quit] cmd)))
+
+      ;; Up returns updated model
+      (let [[new-model cmd] (update-fn model [:key :up])]
+        (is (= {:n 1} new-model))
+        (is (nil? cmd)))
+
+      ;; Unknown key returns model unchanged
+      (let [[new-model cmd] (update-fn model [:key {:char \x}])]
+        (is (= model new-model))
+        (is (nil? cmd))))))
+
+;; =============================================================================
+;; COUNTER PATTERN TESTS (from counter example, works with simple runtime)
+;; =============================================================================
+
+(deftest simple-counter-pattern-test
+  (testing "counter update pattern without async commands"
+    (let [update-fn (fn [{:keys [count] :as model} msg]
+                      (cond
+                        (or (simple/key= msg "q")
+                            (simple/key= msg [:ctrl \c]))
+                        [model simple/quit]
+
+                        (or (simple/key= msg :up)
+                            (simple/key= msg "k"))
+                        [(update model :count inc) nil]
+
+                        (or (simple/key= msg :down)
+                            (simple/key= msg "j"))
+                        [(update model :count dec) nil]
+
+                        (simple/key= msg "r")
+                        [(assoc model :count 0) nil]
+
+                        :else
+                        [model nil]))]
+
+      ;; Test increment with up arrow
+      (let [[m1 _] (update-fn {:count 0} [:key :up])]
+        (is (= 1 (:count m1))))
+
+      ;; Test increment with k
+      (let [[m1 _] (update-fn {:count 0} [:key {:char \k}])]
+        (is (= 1 (:count m1))))
+
+      ;; Test decrement
+      (let [[m1 _] (update-fn {:count 5} [:key :down])]
+        (is (= 4 (:count m1))))
+
+      ;; Test reset
+      (let [[m1 _] (update-fn {:count 42} [:key {:char \r}])]
+        (is (= 0 (:count m1))))
+
+      ;; Test quit with q
+      (let [[_ cmd] (update-fn {:count 0} [:key {:char \q}])]
+        (is (= simple/quit cmd)))
+
+      ;; Test quit with ctrl+c
+      (let [[_ cmd] (update-fn {:count 0} [:key {:ctrl true :char \c}])]
+        (is (= simple/quit cmd))))))
+
+;; =============================================================================
+;; LIST SELECTION PATTERN TESTS (works with simple runtime)
+;; =============================================================================
+
+(deftest simple-list-selection-pattern-test
+  (testing "list selection with cursor navigation"
+    (let [items ["Pizza" "Sushi" "Tacos" "Burger"]
+          update-fn (fn [{:keys [cursor items] :as model} msg]
+                      (cond
+                        (or (simple/key= msg :up)
+                            (simple/key= msg "k"))
+                        [(update model :cursor #(max 0 (dec %))) nil]
+
+                        (or (simple/key= msg :down)
+                            (simple/key= msg "j"))
+                        [(update model :cursor #(min (dec (count items)) (inc %))) nil]
+
+                        (simple/key= msg " ")
+                        [(update model :selected
+                                 #(if (contains? % cursor)
+                                    (disj % cursor)
+                                    (conj % cursor)))
+                         nil]
+
+                        (simple/key= msg :enter)
+                        [(assoc model :submitted true) simple/quit]
+
+                        :else
+                        [model nil]))]
+
+      ;; Test cursor bounds - can't go below 0
+      (let [[m1 _] (update-fn {:cursor 0 :items items :selected #{}} [:key :up])]
+        (is (= 0 (:cursor m1))))
+
+      ;; Test cursor bounds - can't go above max
+      (let [[m1 _] (update-fn {:cursor 3 :items items :selected #{}} [:key :down])]
+        (is (= 3 (:cursor m1))))
+
+      ;; Test toggle selection
+      (let [m0 {:cursor 1 :items items :selected #{}}
+            [m1 _] (update-fn m0 [:key {:char \space}])
+            [m2 _] (update-fn m1 [:key {:char \space}])]
+        (is (= #{1} (:selected m1)))
+        (is (= #{} (:selected m2))))
+
+      ;; Test submission
+      (let [[m1 cmd] (update-fn {:cursor 0 :items items :selected #{0 2} :submitted false}
+                                [:key :enter])]
+        (is (:submitted m1))
+        (is (= simple/quit cmd))))))
+
+;; =============================================================================
+;; VIEWS STATE MACHINE TESTS (works with simple runtime)
+;; =============================================================================
+
+(deftest simple-views-state-machine-test
+  (testing "view state transitions"
+    (let [items [{:name "Profile" :desc "Profile settings"}
+                 {:name "Settings" :desc "App preferences"}]
+          update-fn (fn [{:keys [view cursor items] :as model} msg]
+                      (case view
+                        :menu
+                        (cond
+                          (simple/key= msg :enter)
+                          [(assoc model :view :detail :selected (nth items cursor)) nil]
+                          (simple/key= msg "q")
+                          [model simple/quit]
+                          :else [model nil])
+
+                        :detail
+                        (cond
+                          (or (simple/key= msg :escape)
+                              (simple/key= msg "b"))
+                          [(assoc model :view :menu :selected nil) nil]
+                          (simple/key= msg "q")
+                          [(assoc model :view :confirm) nil]
+                          :else [model nil])
+
+                        :confirm
+                        (cond
+                          (simple/key= msg "y")
+                          [model simple/quit]
+                          (simple/key= msg "n")
+                          [(assoc model :view :detail) nil]
+                          :else [model nil])))]
+
+      ;; Menu -> Detail
+      (let [[m1 _] (update-fn {:view :menu :cursor 0 :items items} [:key :enter])]
+        (is (= :detail (:view m1)))
+        (is (= "Profile" (:name (:selected m1)))))
+
+      ;; Detail -> Menu (back)
+      (let [[m1 _] (update-fn {:view :detail :selected (first items)} [:key :escape])]
+        (is (= :menu (:view m1)))
+        (is (nil? (:selected m1))))
+
+      ;; Detail -> Confirm (quit attempt)
+      (let [[m1 _] (update-fn {:view :detail} [:key {:char \q}])]
+        (is (= :confirm (:view m1))))
+
+      ;; Confirm -> Quit (yes)
+      (let [[_ cmd] (update-fn {:view :confirm} [:key {:char \y}])]
+        (is (= simple/quit cmd)))
+
+      ;; Confirm -> Detail (no)
+      (let [[m1 _] (update-fn {:view :confirm} [:key {:char \n}])]
+        (is (= :detail (:view m1)))))))