gtestutils: add g_test_trap_subprocess()

g_test_trap_fork() doesn't work on Windows and is potentially flaky on
unix anyway given the fork-but-don't-exec. Replace it with
g_test_trap_subprocess(), which re-spawns the same program with
arguments telling it to run a specific (otherwise-ignored) test case.

Make the existing g_test_trap_fork() unit tests be unix-only (they
never passed on Windows anyway), and add a parallel set of
g_test_trap_subprocess() tests.

Also fix the logic of gtestutils's "-p" argument (which is used by the
subprocess tests); previously if you had tests "/foo/bar" and
"/foo/bar/baz", and ran the test program with "-p /foo/bar/baz", it
would run "/foo/bar" too. Fix that and add tests.

https://bugzilla.gnome.org/show_bug.cgi?id=679683

docs/reference/glib/glib-sections.txt

@@ -2907,6 +2907,7 @@ g_test_perf
 g_test_verbose
 g_test_undefined
 g_test_quiet
+g_test_subprocess
 g_test_run
 GTestFunc
 g_test_add_func
@@ -2934,7 +2935,7 @@ g_test_expect_message
 g_test_assert_expected_messages
 
 GTestTrapFlags
-g_test_trap_fork
+g_test_trap_subprocess
 g_test_trap_has_passed
 g_test_trap_reached_timeout
 g_test_trap_assert_passed
@@ -2943,6 +2944,7 @@ g_test_trap_assert_stdout
 g_test_trap_assert_stdout_unmatched
 g_test_trap_assert_stderr
 g_test_trap_assert_stderr_unmatched
+g_test_trap_fork
 
 g_test_rand_bit
 g_test_rand_int

glib/gmessages.c

@@ -1097,7 +1097,7 @@ g_assert_warning (const char *log_domain,
  *
  * Note that you cannot use this to test g_error() messages, since
  * g_error() intentionally never returns even if the program doesn't
- * abort; use g_test_trap_fork() in this case.
+ * abort; use g_test_trap_subprocess() in this case.
  *
  * Since: 2.34
  */

glib/gtestutils.h

@@ -104,6 +104,9 @@ void    g_test_init                     (int            *argc,
 #define g_test_verbose()                (g_test_config_vars->test_verbose)
 #define g_test_quiet()                  (g_test_config_vars->test_quiet)
 #define g_test_undefined()              (g_test_config_vars->test_undefined)
+GLIB_AVAILABLE_IN_2_38
+gboolean g_test_subprocess (void);
+
 /* run all tests under toplevel suite (path: /) */
 GLIB_AVAILABLE_IN_ALL
 int     g_test_run                      (void);
@@ -164,7 +167,6 @@ void    g_test_queue_destroy            (GDestroyNotify destroy_func,
                                          gpointer       destroy_data);
 #define g_test_queue_unref(gobject)     g_test_queue_destroy (g_object_unref, gobject)
 
-/* test traps are guards used around forked tests */
 typedef enum {
   G_TEST_TRAP_SILENCE_STDOUT    = 1 << 7,
   G_TEST_TRAP_SILENCE_STDERR    = 1 << 8,
@@ -173,6 +175,18 @@ typedef enum {
 GLIB_AVAILABLE_IN_ALL
 gboolean g_test_trap_fork               (guint64              usec_timeout,
                                          GTestTrapFlags       test_trap_flags);
+
+typedef enum {
+  G_TEST_SUBPROCESS_INHERIT_STDIN  = 1 << 0,
+  G_TEST_SUBPROCESS_INHERIT_STDOUT = 1 << 1,
+  G_TEST_SUBPROCESS_INHERIT_STDERR = 1 << 2,
+} GTestSubprocessFlags;
+
+GLIB_AVAILABLE_IN_2_38
+void     g_test_trap_subprocess         (const char           *test_path,
+                                         guint64               usec_timeout,
+                                         GTestSubprocessFlags  test_flags);
+
 GLIB_AVAILABLE_IN_ALL
 gboolean g_test_trap_has_passed         (void);
 GLIB_AVAILABLE_IN_ALL

glib/tests/testing.c

@@ -118,6 +118,70 @@ test_fork_timeout (void)
   g_assert (g_test_trap_reached_timeout());
 }
 
+static void
+test_subprocess_fail_child (void)
+{
+  g_assert_not_reached ();
+}
+
+static void
+test_subprocess_fail (void)
+{
+  g_test_trap_subprocess ("/trap_subprocess/fail/subprocess", 0, 0);
+  g_test_trap_assert_failed ();
+  g_test_trap_assert_stderr ("*ERROR*test_subprocess_fail_child*should not be reached*");
+}
+
+static void
+test_subprocess_no_such_test_child (void)
+{
+  g_test_trap_subprocess ("/trap_subprocess/this-test-does-not-exist", 0, 0);
+  g_assert_not_reached ();
+}
+
+static void
+test_subprocess_no_such_test (void)
+{
+  g_test_trap_subprocess ("/trap_subprocess/no-such-test/subprocess", 0, 0);
+  g_test_trap_assert_failed ();
+  g_test_trap_assert_stderr ("*test does not exist*");
+  g_test_trap_assert_stderr_unmatched ("*should not be reached*");
+}
+
+static void
+test_subprocess_patterns_child (void)
+{
+  g_print ("some stdout text: somagic17\n");
+  g_printerr ("some stderr text: semagic43\n");
+  exit (0);
+}
+
+static void
+test_subprocess_patterns (void)
+{
+  g_test_trap_subprocess ("/trap_subprocess/patterns/subprocess", 0,  0);
+  g_test_trap_assert_passed ();
+  g_test_trap_assert_stdout ("*somagic17*");
+  g_test_trap_assert_stderr ("*semagic43*");
+}
+
+static void
+test_subprocess_timeout_child (void)
+{
+  /* loop and sleep forever */
+  while (TRUE)
+    g_usleep (1000 * 1000);
+}
+
+static void
+test_subprocess_timeout (void)
+{
+  /* allow child to run for only a fraction of a second */
+  g_test_trap_subprocess ("/trap_subprocess/timeout/subprocess", 0.11 * 1000000, 0);
+  g_test_trap_assert_failed ();
+  g_assert (g_test_trap_reached_timeout ());
+}
+
 /* run a test with fixture setup and teardown */
 typedef struct {
   guint  seed;
@@ -321,6 +385,100 @@ test_expected_messages (void)
   g_test_trap_assert_stderr ("*Did not see expected message CRITICAL*nope*");
 }
 
+static void
+test_dash_p_hidden (void)
+{
+  if (!g_test_subprocess ())
+    g_assert_not_reached ();
+
+  g_print ("Test /misc/dash-p/subprocess/hidden ran\n");
+}
+
+static void
+test_dash_p_hidden_sub (void)
+{
+  if (!g_test_subprocess ())
+    g_assert_not_reached ();
+
+  g_print ("Test /misc/dash-p/subprocess/hidden/sub ran\n");
+}
+
+/* The rest of the dash_p tests will get run by the toplevel test
+ * process, but they shouldn't do anything there.
+ */
+
+static void
+test_dash_p_child (void)
+{
+  if (!g_test_subprocess ())
+    return;
+
+  g_print ("Test /misc/dash-p/child ran\n");
+}
+
+static void
+test_dash_p_child_sub (void)
+{
+  if (!g_test_subprocess ())
+    return;
+
+  g_print ("Test /misc/dash-p/child/sub ran\n");
+}
+
+static void
+test_dash_p_child_sub2 (void)
+{
+  if (!g_test_subprocess ())
+    return;
+
+  g_print ("Test /misc/dash-p/child/sub2 ran\n");
+}
+
+static void
+test_dash_p_child_sub_child (void)
+{
+  if (!g_test_subprocess ())
+    return;
+
+  g_print ("Test /misc/dash-p/child/subprocess ran\n");
+}
+
+static void
+test_dash_p (void)
+{
+  g_test_trap_subprocess ("/misc/dash-p/subprocess/hidden", 0, 0);
+  g_test_trap_assert_passed ();
+  g_test_trap_assert_stdout ("*Test /misc/dash-p/subprocess/hidden ran*");
+  g_test_trap_assert_stdout_unmatched ("*Test /misc/dash-p/subprocess/hidden/sub ran*");
+  g_test_trap_assert_stdout_unmatched ("*Test /misc/dash-p/subprocess/hidden/sub2 ran*");
+  g_test_trap_assert_stdout_unmatched ("*Test /misc/dash-p/subprocess/hidden/sub/subprocess ran*");
+  g_test_trap_assert_stdout_unmatched ("*Test /misc/dash-p/child*");
+
+  g_test_trap_subprocess ("/misc/dash-p/subprocess/hidden/sub", 0, 0);
+  g_test_trap_assert_passed ();
+  g_test_trap_assert_stdout ("*Test /misc/dash-p/subprocess/hidden/sub ran*");
+  g_test_trap_assert_stdout_unmatched ("*Test /misc/dash-p/subprocess/hidden ran*");
+  g_test_trap_assert_stdout_unmatched ("*Test /misc/dash-p/subprocess/hidden/sub2 ran*");
+  g_test_trap_assert_stdout_unmatched ("*Test /misc/dash-p/subprocess/hidden/subprocess ran*");
+  g_test_trap_assert_stdout_unmatched ("*Test /misc/dash-p/child*");
+
+  g_test_trap_subprocess ("/misc/dash-p/child", 0, 0);
+  g_test_trap_assert_passed ();
+  g_test_trap_assert_stdout ("*Test /misc/dash-p/child ran*");
+  g_test_trap_assert_stdout ("*Test /misc/dash-p/child/sub ran*");
+  g_test_trap_assert_stdout ("*Test /misc/dash-p/child/sub2 ran*");
+  g_test_trap_assert_stdout_unmatched ("*Test /misc/dash-p/child/subprocess ran*");
+  g_test_trap_assert_stdout_unmatched ("*Test /misc/dash-p/subprocess/hidden*");
+
+  g_test_trap_subprocess ("/misc/dash-p/child/sub", 0, 0);
+  g_test_trap_assert_passed ();
+  g_test_trap_assert_stdout ("*Test /misc/dash-p/child/sub ran*");
+  g_test_trap_assert_stdout_unmatched ("*Test /misc/dash-p/child ran*");
+  g_test_trap_assert_stdout_unmatched ("*Test /misc/dash-p/child/sub2 ran*");
+  g_test_trap_assert_stdout_unmatched ("*Test /misc/dash-p/child/subprocess ran*");
+  g_test_trap_assert_stdout_unmatched ("*Test /misc/dash-p/subprocess/hidden*");
+}
+
 int
 main (int   argc,
       char *argv[])
@@ -335,12 +493,37 @@ main (int   argc,
   g_test_add ("/misc/primetoul", Fixturetest, (void*) 0xc0cac01a, fixturetest_setup, fixturetest_test, fixturetest_teardown);
   if (g_test_perf())
     g_test_add_func ("/misc/timer", test_timer);
+
+#ifdef G_OS_UNIX
   g_test_add_func ("/forking/fail assertion", test_fork_fail);
   g_test_add_func ("/forking/patterns", test_fork_patterns);
   if (g_test_slow())
     g_test_add_func ("/forking/timeout", test_fork_timeout);
+#endif
+
+  g_test_add_func ("/trap_subprocess/fail", test_subprocess_fail);
+  g_test_add_func ("/trap_subprocess/fail/subprocess", test_subprocess_fail_child);
+  g_test_add_func ("/trap_subprocess/no-such-test", test_subprocess_no_such_test);
+  g_test_add_func ("/trap_subprocess/no-such-test/subprocess", test_subprocess_no_such_test_child);
+  if (g_test_slow ())
+    {
+      g_test_add_func ("/trap_subprocess/timeout", test_subprocess_timeout);
+      g_test_add_func ("/trap_subprocess/timeout/subprocess", test_subprocess_timeout_child);
+    }
+  g_test_add_func ("/trap_subprocess/patterns", test_subprocess_patterns);
+  g_test_add_func ("/trap_subprocess/patterns/subprocess", test_subprocess_patterns_child);
+
   g_test_add_func ("/misc/fatal-log-handler", test_fatal_log_handler);
   g_test_add_func ("/misc/expected-messages", test_expected_messages);
 
+  g_test_add_func ("/misc/dash-p", test_dash_p);
+  g_test_add_func ("/misc/dash-p/child", test_dash_p_child);
+  g_test_add_func ("/misc/dash-p/child/sub", test_dash_p_child_sub);
+  g_test_add_func ("/misc/dash-p/child/sub/subprocess", test_dash_p_child_sub_child);
+  g_test_add_func ("/misc/dash-p/child/sub/subprocess/child", test_dash_p_child_sub_child);
+  g_test_add_func ("/misc/dash-p/child/sub2", test_dash_p_child_sub2);
+  g_test_add_func ("/misc/dash-p/subprocess/hidden", test_dash_p_hidden);
+  g_test_add_func ("/misc/dash-p/subprocess/hidden/sub", test_dash_p_hidden_sub);
+
   return g_test_run();
 }