internal/processtest: add a test for capturing cursor and fullscreen

Updates #2475

internal/processtest/testdata/issue2475.go

@@ -0,0 +1,75 @@
+// Copyright 2023 The Ebitengine 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
+
+package main
+
+import (
+	"fmt"
+	"runtime"
+
+	"github.com/hajimehoshi/ebiten/v2"
+	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
+)
+
+type Game struct {
+	count int
+	x     int
+	y     int
+}
+
+func (g *Game) Update() error {
+	switch g.count {
+	case 0:
+		g.x, g.y = ebiten.CursorPosition()
+	case 20:
+		ebiten.SetFullscreen(true)
+	case 40:
+		ebiten.SetFullscreen(false)
+	case 60:
+		return ebiten.Termination
+	default:
+		if x, y := ebiten.CursorPosition(); g.x != x || g.y != y {
+			return fmt.Errorf("cursor position changed: got: (%d, %d), want: (%d, %d)", x, y, g.x, g.y)
+		}
+	}
+	g.count++
+	return nil
+}
+
+func (g *Game) Draw(screen *ebiten.Image) {
+	x, y := ebiten.CursorPosition()
+	ebitenutil.DebugPrint(screen, fmt.Sprintf("%d, %d", x, y))
+}
+
+func (g *Game) Layout(width, height int) (int, int) {
+	// Using a fixed size matters.
+	// If a window size is changed or fullscreened, the cursor position calculation considers the current screen scale.
+	return 320, 240
+}
+
+func main() {
+	// Mouse is not supported on mobiles.
+	// Capturing a cursor requires a user gesture on browsers.
+	// Skip the test in these environments.
+	if runtime.GOOS == "android" || runtime.GOOS == "ios" || runtime.GOOS == "js" {
+		return
+	}
+
+	ebiten.SetCursorMode(ebiten.CursorModeCaptured)
+	if err := ebiten.RunGame(&Game{}); err != nil {
+		panic(err)
+	}
+}