initial channel data fetch test

Author: stanistan

render_with_data_fetch_test.go

@@ -0,0 +1,68 @@
+package veun_test
+
+import (
+	"fmt"
+	"html/template"
+	"testing"
+	"time"
+
+	"github.com/alecthomas/assert/v2"
+
+	. "github.com/stanistan/veun"
+)
+
+type ExpensiveViewData struct {
+	Title string `json:"title"`
+}
+
+var expensiveViewTpl = MustParseTemplate("expensiveView", `{{ .Title }} success`)
+
+type ExpensiveView struct {
+	Data chan ExpensiveViewData
+	Err  chan error
+}
+
+func NewExpensiveView(shouldErr bool) *ExpensiveView {
+	errCh := make(chan error)
+	dataCh := make(chan ExpensiveViewData)
+
+	go func() {
+		defer func() {
+			close(errCh)
+			close(dataCh)
+		}()
+
+		// do data fetching and either write to
+		// one thing or the other
+		time.Sleep(1 * time.Millisecond)
+		if shouldErr {
+			errCh <- fmt.Errorf("fetch failed")
+		} else {
+			dataCh <- ExpensiveViewData{Title: "hi"}
+		}
+	}()
+
+	return &ExpensiveView{Data: dataCh, Err: errCh}
+}
+
+func (v *ExpensiveView) Renderable() (Renderable, error) {
+	select {
+	case err := <-v.Err:
+		return nil, err
+	case data := <-v.Data:
+		return View{Tpl: expensiveViewTpl, Data: data}, nil
+	}
+}
+
+func TestViewWithChannels(t *testing.T) {
+	t.Run("successful", func(t *testing.T) {
+		html, err := Render(NewExpensiveView(false))
+		assert.NoError(t, err)
+		assert.Equal(t, template.HTML(`hi success`), html)
+	})
+
+	t.Run("failed", func(t *testing.T) {
+		_, err := Render(NewExpensiveView(true))
+		assert.Error(t, err)
+	})
+}