Refactor: Toaster returns its wake time instead of storing it

toastQueue.wake kept state only tests read. Toaster now reports the
frame's wake time in an unexported ToasterResult field, and
TestToastExpiresAndHoverPauses asserts on the returned value.

toast.go

@@ -32,6 +32,7 @@ type ToastMessage struct {
 type ToasterResult struct {
 	Action string
 	Closed string
+	wake   time.Time // when this frame asked for the next one; zero for none
 }
 
 type toastItem struct {
@@ -46,7 +47,6 @@ type toastItem struct {
 // toastQueue holds a window's toasts, visible ones first in order shown.
 type toastQueue struct {
 	items []toastItem
-	wake  time.Time // when Toaster last asked for a frame; zero for none
 }
 
 type toastKey struct{}
@@ -231,9 +231,8 @@ func Toaster(c *ui.Context) ToasterResult {
 		}
 	}
 	// Scheduled after resuming, so a toast released this frame still expires.
-	q.wake = time.Time{}
 	if next := q.settle(now, held); next > 0 {
-		q.wake = now.Add(next)
+		res.wake = now.Add(next)
 		c.After(next)
 	}
 	return res

toast_test.go

@@ -158,23 +158,22 @@ func TestToastKeepsFocusAndEscapeCloses(t *testing.T) {
 }
 
 func TestToastExpiresAndHoverPauses(t *testing.T) {
-	var q *toastQueue
+	var res ToasterResult
 	const life = 40 * time.Millisecond
 	tt := ui.NewTester(func(c *ui.Context) {
 		Use(c, Settings{})
 		if Button(c, "Notify", ButtonOptions{}).Clicked() {
 			ShowToast(c, ToastMessage{Message: "Copied", Duration: life})
 		}
-		q = toasts(c)
-		Toaster(c)
+		res = Toaster(c)
 	}, 600, 400)
 	_ = tt.Click("Notify")
-	if q.wake.IsZero() {
+	if res.wake.IsZero() {
 		t.Fatal("no wake-up scheduled for a running toast")
 	}
 	r, _ := tt.Find("Copied")
 	tt.Move(r.X+r.W/2, r.Y+r.H/2)
-	if !q.wake.IsZero() {
+	if !res.wake.IsZero() {
 		t.Fatal("hovered toast still schedules its expiry")
 	}
 	time.Sleep(2 * life)
@@ -182,14 +181,14 @@ func TestToastExpiresAndHoverPauses(t *testing.T) {
 	tt.Move(5, 395)
 	done := time.Now()
 	// The frame that ends the hover must schedule the expiry itself.
-	if q.wake.IsZero() || q.wake.Before(released) || q.wake.After(done.Add(life)) {
-		t.Fatalf("release scheduled wake %v, released %v", q.wake, released)
+	if res.wake.IsZero() || res.wake.Before(released) || res.wake.After(done.Add(life)) {
+		t.Fatalf("release scheduled wake %v, released %v", res.wake, released)
 	}
 	if !tt.HasText("Copied") {
 		t.Fatal("hovered toast expired")
 	}
-	// Stands in for the frame MyGo's timer runs at q.wake.
-	time.Sleep(time.Until(q.wake) + 5*time.Millisecond)
+	// Stands in for the frame MyGo's timer runs at res.wake.
+	time.Sleep(time.Until(res.wake) + 5*time.Millisecond)
 	tt.Frame()
 	if tt.HasText("Copied") {
 		t.Fatal("toast stayed after its wake-up")