internal/processtest/testdata: add a test case for #2089

Updates #2089

internal/processtest/testdata/issue2089.go

@@ -0,0 +1,78 @@
+// Copyright 2022 The Ebiten Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build ignore
+// +build ignore
+
+package main
+
+import (
+	"errors"
+	"fmt"
+	"image/color"
+
+	"github.com/hajimehoshi/ebiten/v2"
+)
+
+var regularTermination = errors.New("regular termination")
+
+type Game struct {
+	count int
+}
+
+func (g *Game) Update() error {
+	g.count++
+	if g.count == 16 {
+		return regularTermination
+	}
+
+	w, h := 256+g.count, 256+g.count
+	img := ebiten.NewImage(w, h)
+	img.Fill(color.White)
+	for j := 0; j < h; j++ {
+		for i := 0; i < w; i++ {
+			if (i+j)%3 == 0 {
+				img.Set(i, j, color.Black)
+			}
+		}
+	}
+
+	for j := 0; j < h; j++ {
+		for i := 0; i < w; i++ {
+			want := color.RGBA{0xff, 0xff, 0xff, 0xff}
+			if (i+j)%3 == 0 {
+				want = color.RGBA{0, 0, 0, 0xff}
+			}
+			got := img.At(i, j)
+			if got != want {
+				panic(fmt.Sprintf("At(%d, %d): got: %v, want: %v", i, j, got, want))
+			}
+		}
+	}
+
+	return nil
+}
+
+func (g *Game) Draw(screen *ebiten.Image) {
+}
+
+func (g *Game) Layout(width, height int) (int, int) {
+	return width, height
+}
+
+func main() {
+	if err := ebiten.RunGame(&Game{}); err != nil && err != regularTermination {
+		panic(err)
+	}
+}