[glib/wip/test-fail-convenience: 29/30] gtestutils: Allow failing a test with a printf-style message

[Simon McVittie <smcv src gnome org>]

commit a076dbcb68df592595ce77e76766dfc534bd529d
Author: Simon McVittie <smcv collabora com>
Date:   Thu Aug 5 11:42:22 2021 +0100

    gtestutils: Allow failing a test with a printf-style message
    
    This allows a pattern like
    
        g_test_message ("cannot reticulate splines: %s", error->message);
        g_test_fail ();
    
    to be replaced by the simpler
    
        g_test_fail_printf ("cannot reticulate splines: %s", error->message);
    
    with the secondary benefit of making the message available to TAP
    consumers as part of the "not ok" message.
    
    Signed-off-by: Simon McVittie <smcv collabora com>

 docs/reference/glib/glib-sections.txt |  1 +
 glib/gtestutils.c                     | 32 ++++++++++++++++++++++++++++++++
 glib/gtestutils.h                     |  3 +++
 glib/tests/testing-helper.c           | 10 ++++++++++
 glib/tests/testing.c                  | 20 ++++++++++++++++++++
 5 files changed, 66 insertions(+)
---
diff --git a/docs/reference/glib/glib-sections.txt b/docs/reference/glib/glib-sections.txt
index 6e4216809..6533764e1 100644
--- a/docs/reference/glib/glib-sections.txt
+++ b/docs/reference/glib/glib-sections.txt
@@ -3569,6 +3569,7 @@ g_test_get_filename
 g_test_get_dir
 
 g_test_fail
+g_test_fail_printf
 g_test_skip
 g_test_skip_printf
 g_test_incomplete
diff --git a/glib/gtestutils.c b/glib/gtestutils.c
index f27ad2636..578270394 100644
--- a/glib/gtestutils.c
+++ b/glib/gtestutils.c
@@ -1039,6 +1039,8 @@ g_test_log (GTestLogType lbit,
             g_print (" # TODO %s\n", string2 ? string2 : "");
           else if (result == G_TEST_RUN_SKIPPED)
             g_print (" # SKIP %s\n", string2 ? string2 : "");
+          else if (result == G_TEST_RUN_FAILURE && string2 != NULL)
+            g_print (" - %s\n", string2);
           else
             g_print ("\n");
         }
@@ -2401,12 +2403,42 @@ g_test_add_vtable (const char       *testpath,
  *
  * If not called from inside a test, this function does nothing.
  *
+ * Note that unlike g_test_skip() and g_test_incomplete(), this
+ * function does not log a message alongside the test failure.
+ * If details of the test failure are available, either log them with
+ * g_test_message() before g_test_fail(), or use g_test_fail_printf()
+ * instead.
+ *
  * Since: 2.30
  **/
 void
 g_test_fail (void)
 {
   test_run_success = G_TEST_RUN_FAILURE;
+  g_clear_pointer (&test_run_msg, g_free);
+}
+
+/**
+ * g_test_fail_printf:
+ * @format: the format string
+ * @...:    printf-like arguments to @format
+ *
+ * Equivalent to g_test_fail(), but also record a message like
+ * g_test_skip_printf().
+ *
+ * Since: 2.70
+ **/
+void
+g_test_fail_printf (const char *format,
+                    ...)
+{
+  va_list args;
+
+  test_run_success = G_TEST_RUN_FAILURE;
+  va_start (args, format);
+  g_free (test_run_msg);
+  test_run_msg = g_strdup_vprintf (format, args);
+  va_end (args);
 }
 
 /**
diff --git a/glib/gtestutils.h b/glib/gtestutils.h
index 524344b72..f5202ac44 100644
--- a/glib/gtestutils.h
+++ b/glib/gtestutils.h
@@ -345,6 +345,9 @@ const char * g_test_get_path            (void);
 /* tell about failure */
 GLIB_AVAILABLE_IN_2_30
 void    g_test_fail                     (void);
+GLIB_AVAILABLE_IN_2_70
+void    g_test_fail_printf              (const char *format,
+                                         ...) G_GNUC_PRINTF (1, 2);
 GLIB_AVAILABLE_IN_2_38
 void    g_test_incomplete               (const gchar *msg);
 GLIB_AVAILABLE_IN_2_70
diff --git a/glib/tests/testing-helper.c b/glib/tests/testing-helper.c
index 9c30b01b8..7b61e8337 100644
--- a/glib/tests/testing-helper.c
+++ b/glib/tests/testing-helper.c
@@ -49,6 +49,12 @@ test_fail (void)
   g_test_fail ();
 }
 
+static void
+test_fail_printf (void)
+{
+  g_test_fail_printf ("this test intentionally left failing");
+}
+
 static void
 test_incomplete (void)
 {
@@ -123,6 +129,10 @@ main (int   argc,
     {
       g_test_add_func ("/fail", test_fail);
     }
+  else if (g_strcmp0 (argv1, "fail-printf") == 0)
+    {
+      g_test_add_func ("/fail-printf", test_fail_printf);
+    }
   else if (g_strcmp0 (argv1, "all-non-failures") == 0)
     {
       g_test_add_func ("/pass", test_pass);
diff --git a/glib/tests/testing.c b/glib/tests/testing.c
index a646f7c71..03cfe03e1 100644
--- a/glib/tests/testing.c
+++ b/glib/tests/testing.c
@@ -1177,6 +1177,26 @@ test_tap (void)
   g_clear_error (&error);
   g_ptr_array_unref (argv);
 
+  g_test_message ("fail with message");
+  argv = g_ptr_array_new ();
+  g_ptr_array_add (argv, (char *) testing_helper);
+  g_ptr_array_add (argv, "fail-printf");
+  g_ptr_array_add (argv, "--tap");
+  g_ptr_array_add (argv, NULL);
+
+  g_spawn_sync (NULL, (char **) argv->pdata, NULL,
+                G_SPAWN_STDERR_TO_DEV_NULL,
+                NULL, NULL, &output, NULL, &status,
+                &error);
+  g_assert_no_error (error);
+
+  g_spawn_check_wait_status (status, &error);
+  g_assert_error (error, G_SPAWN_EXIT_ERROR, 1);
+  g_assert_nonnull (strstr (output, "\nnot ok 1 /fail-printf - this test intentionally left failing\n"));
+  g_free (output);
+  g_clear_error (&error);
+  g_ptr_array_unref (argv);
+
   g_test_message ("all");
   argv = g_ptr_array_new ();
   g_ptr_array_add (argv, (char *) testing_helper);