Add test for double-click detection

Add a test pinning down that a press/release/press sequence at the
same position is detected as a double click. An upcoming commit starts
delivering the release as a real mouse event to the click-recording
code, which must not mistake it for a click of its own.

pkg/gocui/double_click_test.go

@@ -0,0 +1,34 @@
+package gocui
+
+import (
+	"testing"
+
+	"github.com/gdamore/tcell/v3"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMouseReleaseDoesNotBreakDoubleClickDetection(t *testing.T) {
+	t.Cleanup(resetMouseState)
+	resetMouseState()
+	g := newTestGui(t)
+	view, _ := g.SetView("list", 0, 0, 20, 10, 0)
+	doubleClicks := []bool{}
+	assert.NoError(t, g.SetViewClickBinding(&ViewMouseBinding{
+		ViewName: "list",
+		Key:      MouseLeft,
+		Handler: func(opts ViewMouseBindingOpts) error {
+			doubleClicks = append(doubleClicks, opts.IsDoubleClick)
+			return nil
+		},
+	}))
+
+	for _, event := range []GocuiEvent{
+		gocuiEventFromTcellEvent(tcell.NewEventMouse(view.x0+1, view.y0+1, tcell.ButtonPrimary, tcell.ModNone)),
+		gocuiEventFromTcellEvent(tcell.NewEventMouse(view.x0+1, view.y0+1, tcell.ButtonNone, tcell.ModNone)),
+		gocuiEventFromTcellEvent(tcell.NewEventMouse(view.x0+1, view.y0+1, tcell.ButtonPrimary, tcell.ModNone)),
+	} {
+		assert.NoError(t, g.onKey(&event))
+	}
+
+	assert.Equal(t, []bool{false, true}, doubleClicks)
+}