gtestutils: add g_assert_nonnull() to go with g_assert_null()

https://bugzilla.gnome.org/show_bug.cgi?id=711800

docs/reference/glib/glib-sections.txt

@@ -2977,6 +2977,7 @@ g_assert_error
 g_assert_true
 g_assert_false
 g_assert_null
+g_assert_nonnull
 g_test_set_nonfatal_assertions
 
 GTestCase

glib/gtestutils.c

@@ -391,6 +391,21 @@
  * Since: 2.38
  */
 
+/**
+ * g_assert_nonnull:
+ * @expr: the expression to check
+ *
+ * Debugging macro to check an expression is not %NULL.
+ *
+ * If the assertion fails (i.e. the expression is %NULL),
+ * an error message is logged and the application is either
+ * terminated or the testcase marked as failed.
+ *
+ * See g_test_set_nonfatal_assertions().
+ *
+ * Since: 2.40
+ */
+
 /**
  * g_assert_cmpstr:
  * @s1: a string (may be %NULL)

glib/gtestutils.h

@@ -74,7 +74,11 @@ typedef void (*GTestFixtureFunc) (gpointer      fixture,
                                                g_assertion_message (G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, \
                                                                     #expr); \
                                            } while (0)
-#define g_assert_null(expr)              do { if G_LIKELY ((expr) == NULL) ; else \
+#define g_assert_null(expr)             do { if G_LIKELY ((expr) == NULL) ; else \
+                                               g_assertion_message (G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, \
+                                                                    #expr); \
+                                           } while (0)
+#define g_assert_nonnull(expr)          do { if G_LIKELY ((expr) != NULL) ; else \
                                                g_assertion_message (G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, \
                                                                     #expr); \
                                            } while (0)