[glib] gtestutils: Allow clean simple use of g_test_trap_subprocess()

[Matthias Clasen <matthiasc src gnome org>]

commit cd2204bb65114e5ac62b014e6167a659aa254361
Author: Stef Walter <stefw gnome org>
Date:   Wed Dec 11 09:31:35 2013 +0100

    gtestutils: Allow clean simple use of g_test_trap_subprocess()
    
    Allow g_test_trap_subprocess() to be used in a simple cases by
    rerunning the same test case itself. This is accomplished by
    passing %NULL as the test case name.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=720236

 glib/gtestutils.c |   40 ++++++++++++++++++++++++----------------
 glib/tests/list.c |   35 +++++++++++++++++------------------
 2 files changed, 41 insertions(+), 34 deletions(-)
---
diff --git a/glib/gtestutils.c b/glib/gtestutils.c
index c2d0c6a..bc7bbcf 100644
--- a/glib/gtestutils.c
+++ b/glib/gtestutils.c
@@ -2738,13 +2738,19 @@ g_test_trap_fork (guint64        usec_timeout,
 
 /**
  * g_test_trap_subprocess:
- * @test_path:    Test to run in a subprocess
+ * @test_path: (allow-none): Test to run in a subprocess
  * @usec_timeout: Timeout for the subprocess test in micro seconds.
  * @test_flags:   Flags to modify subprocess behaviour.
  *
  * Respawns the test program to run only @test_path in a subprocess.
  * This can be used for a test case that might not return, or that
- * might abort. @test_path will normally be the name of the parent
+ * might abort.
+ *
+ * If @test_path is %NULL then the same test is re-run in a subprocess.
+ * You can use g_test_subprocess() to determine whether the test is in
+ * a subprocess or not.
+ *
+ * @test_path can also be the name of the parent
  * test, followed by "<literal>/subprocess/</literal>" and then a name
  * for the specific subtest (or just ending with
  * "<literal>/subprocess</literal>" if the test only has one child
@@ -2776,13 +2782,14 @@ g_test_trap_fork (guint64        usec_timeout,
  *   static void
  *   test_create_large_object_subprocess (void)
  *   {
- *     my_object_new (1000000);
- *   }
+ *     if (g_test_subprocess ())
+ *       {
+ *         my_object_new (1000000);
+ *         return;
+ *       }
  *
- *   static void
- *   test_create_large_object (void)
- *   {
- *     g_test_trap_subprocess ("/myobject/create_large_object/subprocess", 0, 0);
+ *     /&ast; Reruns this same test in a subprocess &ast;/
+ *     g_test_trap_subprocess (NULL, 0, 0);
  *     g_test_trap_assert_failed ();
  *     g_test_trap_assert_stderr ("*ERROR*too large*");
  *   }
@@ -2794,12 +2801,6 @@ g_test_trap_fork (guint64        usec_timeout,
  *
  *     g_test_add_func ("/myobject/create_large_object",
  *                      test_create_large_object);
- *     /&ast; Because of the '/subprocess' in the name, this test will
- *      &ast; not be run by the g_test_run () call below.
- *      &ast;/
- *     g_test_add_func ("/myobject/create_large_object/subprocess",
- *                      test_create_large_object_subprocess);
- *
  *     return g_test_run ();
  *   }
  * ]|
@@ -2820,8 +2821,15 @@ g_test_trap_subprocess (const char           *test_path,
   /* Sanity check that they used GTestSubprocessFlags, not GTestTrapFlags */
   g_assert ((test_flags & (G_TEST_TRAP_INHERIT_STDIN | G_TEST_TRAP_SILENCE_STDOUT | 
G_TEST_TRAP_SILENCE_STDERR)) == 0);
 
-  if (!g_test_suite_case_exists (g_test_get_root (), test_path))
-    g_error ("g_test_trap_subprocess: test does not exist: %s", test_path);
+  if (test_path)
+    {
+      if (!g_test_suite_case_exists (g_test_get_root (), test_path))
+        g_error ("g_test_trap_subprocess: test does not exist: %s", test_path);
+    }
+  else
+    {
+      test_path = test_run_name;
+    }
 
   if (g_test_verbose ())
     g_print ("GTest: subprocess: %s\n", test_path);
diff --git a/glib/tests/list.c b/glib/tests/list.c
index 28cf8e9..a53e326 100644
--- a/glib/tests/list.c
+++ b/glib/tests/list.c
@@ -490,28 +490,28 @@ test_position (void)
 }
 
 static void
-test_double_free_subprocess (void)
+test_double_free (void)
 {
   GList *list, *link;
   GList  intruder = { NULL, (gpointer)0xDEADBEEF, (gpointer)0xDEADBEEF };
 
-  list = NULL;
-  list = g_list_append (list, "a");
-  link = list = g_list_append (list, "b");
-  list = g_list_append (list, "c");
-
-  list = g_list_remove_link (list, link);
-  link->prev = list;
-  link->next = &intruder;
-  list = g_list_remove_link (list, link);
-
-  g_list_free (list);
-}
+  if (g_test_subprocess ())
+    {
+      list = NULL;
+      list = g_list_append (list, "a");
+      link = list = g_list_append (list, "b");
+      list = g_list_append (list, "c");
+
+      list = g_list_remove_link (list, link);
+      link->prev = list;
+      link->next = &intruder;
+      list = g_list_remove_link (list, link);
+
+      g_list_free (list);
+      return;
+    }
 
-static void
-test_double_free (void)
-{
-  g_test_trap_subprocess ("/list/double-free/subprocess", 0, 0);
+  g_test_trap_subprocess (NULL, 0, 0);
   g_test_trap_assert_failed ();
   g_test_trap_assert_stderr ("*corrupted double-linked list detected*");
 }
@@ -545,7 +545,6 @@ main (int argc, char *argv[])
   g_test_add_func ("/list/prepend", test_prepend);
   g_test_add_func ("/list/position", test_position);
   g_test_add_func ("/list/double-free", test_double_free);
-  g_test_add_func ("/list/double-free/subprocess", test_double_free_subprocess);
 
   return g_test_run ();
 }