mal-go/list/list_test.go
ajet 465c959414
All checks were successful
Go / test (push) Successful in 4s
strengthen constraint
2025-11-05 04:54:02 -10:00

92 lines
2.6 KiB
Go

package list
import (
"regexp"
"strings"
"testing"
"github.com/stretchr/testify/assert"
"pgregory.net/rapid"
)
// intListGen returns a generator for either empty list or random ints
func intListGen() *rapid.Generator[IList] {
return rapid.OneOf(rapid.Custom(func(t *rapid.T) IList {
myList := Empty()
t.Repeat(map[string]func(*rapid.T){
"conj": func(t *rapid.T) {
myList = myList.Conj(rapid.Int().Draw(t, "el"))
},
})
return myList
}), rapid.Just(Empty()))
}
// descSortedIntListGen returns a generator for list of at least several descending ints
func descSortedIntListGen() *rapid.Generator[IList] {
return rapid.Custom(func(t *rapid.T) IList {
myList := New(0)
i := 1
t.Repeat(map[string]func(*rapid.T){
"conj": func(t *rapid.T) {
myList = myList.Conj(i)
i += 1
},
})
return myList
}).Filter(func(l IList) bool {
return l.Len() > 1
})
}
func TestFirstIsNilOnlyWhenEmpty(t *testing.T) {
assert.Equal(t, 1, New(3).Conj(2).Conj(1).First())
rapid.Check(t, func(t *rapid.T) {
myList := intListGen().Draw(t, "myList")
assert.Equal(t, myList.IsEmpty(), myList.First() == nil, "first is nil only when list is empty")
})
}
func TestConj(t *testing.T) {
rapid.Check(t, func(t *rapid.T) {
myList := intListGen().Draw(t, "myList")
newElem := rapid.Int().Draw(t, "newElem")
myList2 := myList.Conj(newElem)
assert.Equal(t, myList.Len()+1, myList2.Len(), "conj increases length")
assert.Equal(t, newElem, myList2.First(), "first after conj returns inserted number")
})
}
func TestRest(t *testing.T) {
rapid.Check(t, func(t *rapid.T) {
myList := intListGen().Draw(t, "myList")
if myList.IsEmpty() {
assert.Equal(t, myList.Len(), myList.Rest().Len(), "rest does not change length for empty list")
} else {
assert.Equal(t, myList.Len()-1, myList.Rest().Len(), "rest decreases length of non-empty list")
}
})
rapid.Check(t, func(t *rapid.T) {
myList := descSortedIntListGen().Draw(t, "myList")
assert.Greater(t, myList.First(), myList.Rest().First(), "rest decreases value in list head")
})
}
func TestStringifyIntList(t *testing.T) {
assert.Equal(t, "(1 2 3)", New(3).Conj(2).Conj(1).String())
rapid.Check(t, func(t *rapid.T) {
myList := intListGen().Draw(t, "myList")
s := myList.String()
r := regexp.MustCompile(`^\([\d\s-]*\)$`)
assert.Equal(t, true, r.Match([]byte(s)), s+" looks like a stringified list")
if !myList.IsEmpty() {
assert.Equal(t, myList.Len(), strings.Count(s, " ")+1, "number of spaces in string should match count of elements")
} else {
assert.Equal(t, 0, strings.Count(s, " "), "no spaces in string for empty list")
}
})
}