Regression test for falling back to autolaunch: and XDG_RUNTIME_DIR/bus

Bug: https://bugzilla.gnome.org/show_bug.cgi?id=747941
Signed-off-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
Reviewed-by: Philip Withnall <philip.withnall@collabora.co.uk>

gio/tests/dbus-launch.c

@@ -0,0 +1,77 @@
+/*
+ * Mock version of dbus-launch, for gdbus-unix-addresses test
+ *
+ * Copyright © 2015 Collabora Ltd.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General
+ * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <glib.h>
+
+#ifndef G_OS_UNIX
+#error This is a Unix-specific test helper
+#endif
+
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#define ME "GDBus mock version of dbus-launch"
+
+static void
+write_all (const void *ptr,
+           size_t      len)
+{
+  const char *p = ptr;
+
+  while (len > 0)
+    {
+      ssize_t done = write (STDOUT_FILENO, p, len);
+
+      if (done == 0)
+        {
+          g_error ("%s: write: EOF", ME);
+        }
+      else if (done < 0)
+        {
+          if (errno == EINTR)
+            continue;
+
+          g_error ("%s: write: %s", ME, g_strerror (errno));
+        }
+      else
+        {
+          if (len < (size_t) done)
+            g_error ("%s: wrote too many bytes?", ME);
+
+          len -= done;
+          p += done;
+        }
+    }
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  pid_t pid = 0x2323;
+  long window_id = 0x42424242;
+  const char *addr = "hello:this=address-is-from-the,mock=dbus-launch";
+
+  write_all (addr, strlen (addr) + 1);
+  write_all (&pid, sizeof (pid));
+  write_all (&window_id, sizeof (window_id));
+  return 0;
+}