Redefine assert

diff --git a/tests/weston-test-runner.c b/tests/weston-test-runner.c
index ef45bae..cabded0 100644
--- a/tests/weston-test-runner.c
+++ b/tests/weston-test-runner.c
@@ -34,6 +34,8 @@

 #define SKIP 77

+int assert_exit_code = SIGABRT;
+
 extern const struct weston_test __start_test_section, __stop_test_section;

diff --git a/tests/weston-test-runner.h b/tests/weston-test-runner.h
index e1db040..7f7cf45 100644
--- a/tests/weston-test-runner.h
+++ b/tests/weston-test-runner.h
@@ -27,11 +27,27 @@
 #include "config.h"

 #include <stdlib.h>
+#include <stdio.h>
+#include <signal.h>

 #ifdef NDEBUG
 #error "Tests must not be built with NDEBUG defined, they rely on assert()."
 #endif

+extern int assert_exit_code;
+
+#define WESTON_TEST_EXPECT_FAILURE do { assert_exit_code = EXIT_SUCCESS; } while (0);
+#define WESTON_TEST_DONT_EXPECT_FAILURE do { assert_exit_code = SIGABRT; } while (0);
+
+#define assert(cond)                                                   \
+       do {                                                            \
+               if (!(cond)) {                                          \
+                       fprintf(stderr, "%s: %d: Assertion %s failed\n",\
+                               __FUNCTION__, __LINE__, #cond);         \
+                       exit(assert_exit_code);                 \
+               }                                                       \
+       } while (0)
+
 struct weston_test {
        const char *name;
        void (*run)(void *);