Ebiten loop in tests

test.go

var regularTermination = errors.New("regular termination")

type game struct {
	m    *testing.M
	code int
}

func (g *game) Update(*ebiten.Image) error {
	g.code = g.m.Run()
	return regularTermination
}

func (*game) Draw(*ebiten.Image) {
}

func (*game) Layout(int, int) (int, int) {
	return 320, 240
}

func mainWithEbiten(m *testing.M) {
	g := &game{
		m: m,
	}
	if err := ebiten.RunGame(g); err != nil && err != regularTermination {
		panic(err)
	}
	os.Exit(g.code)
}

func TestMain(m *testing.M) {
	// Run Ebiten's main loop for rendering.
	mainWithEbiten(m)
}