[folks] tests: Add missing return value to function precondition

[Philip Withnall <pwithnall src gnome org>]

commit 6ec9f9e32681e6b2bfe2b562d8ebae2ab5dc41ad
Author: Ting-Wei Lan <lantw44 gmail com>
Date:   Thu Jan 16 22:56:59 2014 +0000

    tests: Add missing return value to function precondition
    
    https://bugzilla.gnome.org/show_bug.cgi?id=722335

 tests/lib/test-case-helper.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/tests/lib/test-case-helper.c b/tests/lib/test-case-helper.c
index 0011b37..bd5c0ee 100644
--- a/tests/lib/test-case-helper.c
+++ b/tests/lib/test-case-helper.c
@@ -75,7 +75,7 @@ folks_test_case_add_test_helper (FolksTestCase *self,
 {
   FolksTestCaseWeakMethod *wm;
 
-  g_return_if_fail (self == (FolksTestCase *) test_target);
+  g_return_val_if_fail (self == (FolksTestCase *) test_target, NULL);
 
   /* This will never be freed, so make sure not to hold references. */
   wm = g_new0 (FolksTestCaseWeakMethod, 1);