testsuite: Add a basic test for remote clipboards

Unfortunately, Wayland doesn't allow access to the clipboard unless the
display has focus, so no chance of testing it there.

But it works elsewhere.

testsuite/gdk/clipboard.c

@@ -2,10 +2,46 @@
 
 #include <gtk/gtk.h>
 
+#ifdef GDK_WINDOWING_WAYLAND
+#include "wayland/gdkwayland.h"
+#endif
+
 static void
-text_received (GObject *source,
+value_received (GObject      *source,
+                GAsyncResult *res,
+                gpointer      data)
+{
+  GdkClipboard *clipboard = GDK_CLIPBOARD (source);
+  const GValue *value;
+  GValue *expected = data;
+  GError *error = NULL;
+
+  value = gdk_clipboard_read_value_finish (clipboard, res, &error);
+
+  g_assert_nonnull (value);
+  g_assert_no_error (error);
+
+  g_assert_cmpuint (G_VALUE_TYPE (value), ==, G_VALUE_TYPE (expected));
+  
+  if (G_VALUE_TYPE (value) == G_TYPE_STRING)
+    {
+      g_assert_cmpstr (g_value_get_string (value), ==, g_value_get_string (expected));
+    }
+  else
+    {
+      /* Add a comparison for the missing type here */
+      g_assert_cmpuint (G_VALUE_TYPE (value), ==, G_TYPE_INVALID);
+    }
+
+  g_value_unset (expected);
+
+  g_main_context_wakeup (NULL);
+}
+
+static void
+text_received (GObject      *source,
                GAsyncResult *res,
-               gpointer data)
+               gpointer      data)
 {
   GdkClipboard *clipboard = GDK_CLIPBOARD (source);
   gboolean *done = data;
@@ -70,14 +106,98 @@ test_clipboard_basic (void)
   g_value_unset (&value);
 }
 
+static void
+remote_clipboard_sync_changed_cb (GdkClipboard *clipboard,
+                                  gboolean     *done)
+{
+  GdkContentFormats *formats = gdk_clipboard_get_formats (clipboard);
+
+  /* X11 needs to query formats first and reports empty until then */
+  if (gdk_content_formats_get_gtypes (formats, NULL) == NULL &&
+      gdk_content_formats_get_mime_types (formats, NULL) == NULL)
+    return;
+
+  *done = TRUE;
+}
+
+static void
+remote_clipboard_sync (GdkClipboard *clipboard)
+{
+  guint signal;
+  gboolean done;
+
+  done = FALSE;
+  signal = g_signal_connect (clipboard, "changed", G_CALLBACK (remote_clipboard_sync_changed_cb), &done);
+
+  while (!done)
+    g_main_context_iteration (NULL, TRUE);
+
+  g_signal_handler_disconnect (clipboard, signal);
+}
+
+static void
+test_remote_basic (gconstpointer data)
+{
+  GdkDisplay *display, *remote_display;
+  GdkClipboard *clipboard, *remote_clipboard;
+  GdkContentFormats *formats;
+  GValue value = G_VALUE_INIT;
+
+  display = gdk_display_get_default ();
+  clipboard = gdk_display_get_clipboard (display);
+  remote_display = GDK_DISPLAY (data);
+  remote_clipboard = gdk_display_get_clipboard (remote_display);
+
+  g_assert_true (gdk_clipboard_get_display (clipboard) == display);
+  g_assert_true (gdk_clipboard_get_display (remote_clipboard) == remote_display);
+
+  gdk_clipboard_set_text (clipboard, "testing, 1, 2");
+  remote_clipboard_sync (remote_clipboard);
+
+  g_assert_true (gdk_clipboard_is_local (clipboard));
+  g_assert_false (gdk_clipboard_is_local (remote_clipboard));
+  g_assert_null (gdk_clipboard_get_content (remote_clipboard));
+
+  formats = gdk_clipboard_get_formats (remote_clipboard);
+
+  g_assert_true (gdk_content_formats_contain_gtype (formats, G_TYPE_STRING));
+  g_assert_true (gdk_content_formats_contain_mime_type (formats, "text/plain"));
+
+  g_value_init (&value, G_TYPE_STRING);
+  g_value_set_string (&value, "testing, 1, 2");
+  gdk_clipboard_read_value_async (remote_clipboard, G_TYPE_STRING, G_PRIORITY_DEFAULT, NULL, value_received, &value);
+  while (G_IS_VALUE (&value))
+    g_main_context_iteration (NULL, TRUE);
+
+  g_assert_null (gdk_clipboard_get_content (remote_clipboard));
+}
+
 int
 main (int argc, char *argv[])
 {
+  GdkDisplay *remote_display;
+  int result;
+
   g_test_init (&argc, &argv, NULL);
 
   gtk_init ();
 
   g_test_add_func ("/clipboard/basic", test_clipboard_basic);
 
-  return g_test_run ();
+  remote_display = gdk_display_open (NULL);
+
+#ifdef GDK_WINDOWING_WAYLAND
+  if (!GDK_IS_WAYLAND_DISPLAY (remote_display))
+#else
+  if (true)
+#endif
+    {
+      g_test_add_data_func ("/clipboard/remote/basic", remote_display, test_remote_basic);
+    }
+
+  result = g_test_run ();
+
+  g_object_unref (remote_display);
+
+  return result;
 }