Refactor template render (#36438)

routers/common/errpage_test.go

@@ -18,19 +18,28 @@ import (
 )
 
 func TestRenderPanicErrorPage(t *testing.T) {
-	w := httptest.NewRecorder()
-	req := &http.Request{URL: &url.URL{}}
-	req = req.WithContext(reqctx.NewRequestContextForTest(t.Context()))
-	RenderPanicErrorPage(w, req, errors.New("fake panic error (for test only)"))
-	respContent := w.Body.String()
-	assert.Contains(t, respContent, `class="page-content status-page-500"`)
-	assert.Contains(t, respContent, `</html>`)
-	assert.Contains(t, respContent, `lang="en-US"`) // make sure the locale work
+	t.Run("HTML", func(t *testing.T) {
+		w := httptest.NewRecorder()
+		req := &http.Request{URL: &url.URL{}, Header: http.Header{"Accept": []string{"text/html"}}}
+		req = req.WithContext(reqctx.NewRequestContextForTest(t.Context()))
+		RenderPanicErrorPage(w, req, errors.New("fake panic error (for test only)"))
+		respContent := w.Body.String()
+		assert.Contains(t, respContent, `class="page-content status-page-500"`)
+		assert.Contains(t, respContent, `</html>`)
+		assert.Contains(t, respContent, `lang="en-US"`) // make sure the locale work
 
-	// the 500 page doesn't have normal pages footer, it makes it easier to distinguish a normal page and a failed page.
-	// especially when a sub-template causes page error, the HTTP response code is still 200,
-	// the different "footer" is the only way to know whether a page is fully rendered without error.
-	assert.False(t, test.IsNormalPageCompleted(respContent))
+		// the 500 page doesn't have normal pages footer, it makes it easier to distinguish a normal page and a failed page.
+		// especially when a sub-template causes page error, the HTTP response code is still 200,
+		// the different "footer" is the only way to know whether a page is fully rendered without error.
+		assert.False(t, test.IsNormalPageCompleted(respContent))
+	})
+	t.Run("Plain", func(t *testing.T) {
+		w := httptest.NewRecorder()
+		req := &http.Request{URL: &url.URL{}}
+		req = req.WithContext(reqctx.NewRequestContextForTest(t.Context()))
+		renderServiceUnavailable(w, req)
+		assert.Equal(t, "Service Unavailable", w.Body.String())
+	})
 }
 
 func TestMain(m *testing.M) {