Adding test to show that override renders a mobile app tabs on a desk…

…top computer

container/apptabs_override_test.go

@@ -0,0 +1,35 @@
+//go:build !mobile
+
+package container_test
+
+import (
+	"testing"
+
+	"fyne.io/fyne/v2/container"
+	"fyne.io/fyne/v2/test"
+	"fyne.io/fyne/v2/widget"
+)
+
+func TestAppTabs_OverrideMobile(t *testing.T) {
+	test.NewTempApp(t)
+
+	item1 := &container.TabItem{Text: "Test1", Content: widget.NewLabel("Text 1")}
+	item2 := &container.TabItem{Text: "Test2", Content: widget.NewLabel("Text 2")}
+	item3 := &container.TabItem{Text: "Test3", Content: widget.NewLabel("Text 3")}
+	tabs := container.NewAppTabs(item1, item2, item3)
+	w := test.NewWindow(tabs)
+	defer w.Close()
+	w.SetPadded(false)
+	c := w.Canvas()
+
+	min := tabs.MinSize()
+	w.Resize(min)
+
+	test.AssertRendersToMarkup(t, "apptabs/desktop/tab_location_top.xml", c)
+
+	override := container.NewThemeOverride(tabs, test.Theme())
+	override.SetDeviceIsMobile(true)
+	w.Resize(min.AddWidthHeight(-4, -0))
+
+	test.AssertRendersToMarkup(t, "apptabs/mobile/tab_location_top.xml", c)
+}