1 files changed, 33 insertions, 6 deletions
diff --git a/test/assert.c b/test/assert.c
index b252d36..2fa8a89 100644
--- a/test/assert.c
+++ b/test/assert.c
@@ -1,20 +1,47 @@
 #include "assert.h"
 
 #include <signal.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
-void assert(bool cond, const char *cond_str, const char *file, int line,
-            const char *msg) {
+static void assert_internal(bool cond, const char *cond_str, const char *file,
+                            int line, const char *msg, va_list args) {
   if (!cond) {
-    printf("\n%s:%d: assert failed (%s): %s\n", file, line, cond_str, msg);
+    va_list args2;
+    va_copy(args2, args);
+
+    ssize_t res = vsnprintf(NULL, 0, msg, args);
+    char *buf = (char *)msg;
+
+    if (res != -1) {
+      buf = malloc(res + 1);
+      vsnprintf(buf, res + 1, msg, args2);
+    }
+
+    va_end(args);
+
+    printf("\n%s:%d: assert failed (%s): %s\n", file, line, cond_str, buf);
+
+    if (buf != msg) {
+      free(buf);
+    }
     raise(SIGABRT);
   }
 }
 
+void assert(bool cond, const char *cond_str, const char *file, int line,
+            const char *msg, ...) {
+  va_list args;
+  va_start(args, msg);
+  assert_internal(cond, cond_str, file, line, msg, args);
+}
+
 void assert_streq(const char *left, const char *right, const char *file,
-                  int line, const char *msg) {
-  assert(strcmp(left, right) == 0, "<left string> == <right string>", file,
-         line, msg);
+                  int line, const char *msg, ...) {
+  va_list args;
+  va_start(args, msg);
+  assert_internal(strcmp(left, right) == 0, "<left string> == <right string>",
+                  file, line, msg, args);
 }