cmd/gogio: first wayland end-to-end tests

Clicking doesn't quite work yet, but everything else does. We use a
custom sway config to ensure that it's a minimalist setup with no bar or
borders, like the other drivers.

The generic test now adapts to the window's real size when running in
non-headless mode, since tiling window managers resize some drivers like
sway. The default headless mode still expects the exact size that we
specify, as no real windows are at play.

While at it, clean up some now unused code from the x11 file.

Signed-off-by: Daniel Martí <mvdan@mvdan.cc>

cmd/gogio/x11_test.go

@@ -1,9 +1,5 @@
 // SPDX-License-Identifier: Unlicense OR MIT
 
-// TODO(mvdan): come up with an end-to-end platform interface, including methods
-// like "take screenshot" or "close app", so that we can run the same tests on
-// all supported platforms without writing them many times.
-
 package main_test
 
 import (
@@ -93,9 +89,9 @@ func (d *X11TestDriver) Start(t_ *testing.T, path string, width, height int) (cl
 		}
 		cleanups = append(cleanups, cancel)
 		cleanups = append(cleanups, func() {
-			// Give Xserver a chance to exit gracefully, cleaning up
-			// after itself in /tmp. After 10ms, the deferred cancel
-			// above will signal an os.Kill.
+			// Give it a chance to exit gracefully, cleaning up
+			// after itself. After 10ms, the deferred cancel above
+			// will signal an os.Kill.
 			cmd.Process.Signal(os.Interrupt)
 			time.Sleep(10 * time.Millisecond)
 		})
@@ -200,6 +196,7 @@ func (d *X11TestDriver) Click(x, y int) {
 	d.xdotool("mousemove", x, y)
 	d.xdotool("click", "1")
 
+	// Wait for the gio app to render after this click.
 	<-d.frameNotifs
 }
 
@@ -208,18 +205,3 @@ func TestX11(t *testing.T) {
 
 	runEndToEndTest(t, &X11TestDriver{})
 }
-
-// testLogWriter is a bit of a hack to redirect libraries that use a *log.Logger
-// variable to instead send their logs to t.Logf.
-//
-// Since *log.Logger isn't an interface and can only take an io.Writer, all we
-// can do is implement an io.Writer that sends its output to t.Logf. We end up
-// with duplicate log prefixes, but that doesn't seem so bad.
-type testLogWriter struct {
-	t *testing.T
-}
-
-func (w testLogWriter) Write(p []byte) (n int, err error) {
-	w.t.Logf("%s", p)
-	return len(p), nil
-}