io/router: add pointer routing test

Signed-off-by: Elias Naur <mail@eliasnaur.com>

io/router/pointer_test.go

@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package router
+
+import (
+	"image"
+	"testing"
+
+	"gioui.org/f32"
+	"gioui.org/io/event"
+	"gioui.org/io/pointer"
+	"gioui.org/op"
+)
+
+func TestPointer(t *testing.T) {
+	handler1 := new(int)
+	handler2 := new(int)
+	var ops op.Ops
+
+	// Handler 1 area: (0, 0) - (100, 100)
+	pointer.Rect(image.Rectangle{
+		Max: image.Point{
+			X: 100,
+			Y: 100,
+		},
+	}).Add(&ops)
+	pointer.InputOp{Key: handler1}.Add(&ops)
+	// Handler 2 area: (50, 50) - (100, 100) (areas intersect).
+	pointer.Rect(image.Rectangle{
+		Min: image.Point{
+			X: 50,
+			Y: 50,
+		},
+		Max: image.Point{
+			X: 200,
+			Y: 200,
+		},
+	}).Add(&ops)
+	pointer.InputOp{Key: handler2}.Add(&ops)
+
+	var r Router
+	r.Frame(&ops)
+	r.Add(
+		// Hit both handlers.
+		pointer.Event{
+			Type: pointer.Move,
+			Position: f32.Point{
+				X: 50,
+				Y: 50,
+			},
+		},
+		// Hit handler 1.
+		pointer.Event{
+			Type: pointer.Move,
+			Position: f32.Point{
+				X: 49,
+				Y: 50,
+			},
+		},
+		// Hit no handlers.
+		pointer.Event{
+			Type: pointer.Move,
+			Position: f32.Point{
+				X: 100,
+				Y: 50,
+			},
+		},
+	)
+	ev1 := r.Events(handler1)
+	if cancels := countPointerEvents(pointer.Cancel, ev1); cancels != 1 {
+		t.Errorf("got %d cancel events, expected 1", cancels)
+	}
+	ev2 := r.Events(handler2)
+	if cancels := countPointerEvents(pointer.Cancel, ev2); cancels != 1 {
+		t.Errorf("got %d cancel events, expected 1", cancels)
+	}
+	if moves := countPointerEvents(pointer.Move, ev1); moves != 2 {
+		t.Errorf("got %d move events, expected 2", moves)
+	}
+	if moves := countPointerEvents(pointer.Move, ev2); moves != 1 {
+		t.Errorf("got %d move events, expected 1", moves)
+	}
+}
+
+func countPointerEvents(typ pointer.Type, events []event.Event) int {
+	c := 0
+	for _, e := range events {
+		if e, ok := e.(pointer.Event); ok {
+			if e.Type == typ {
+				c++
+			}
+		}
+	}
+	return c
+}