Add log framework

v0/test_log.c

@@ -0,0 +1,21 @@
+#include "test.h"
+#include "log.h"
+#include <string.h>
+
+static char s_lastLoggedError[256];
+
+static void mock_log(const char* msg) {
+    strncpy(s_lastLoggedError, msg, sizeof(s_lastLoggedError) - 1);
+    s_lastLoggedError[sizeof(s_lastLoggedError) - 1] = '\0';
+}
+
+static void test_log_error(void) {
+    log_set_output(mock_log);
+    
+    memset(s_lastLoggedError, 0, sizeof(s_lastLoggedError));
+    log_error("test error message");
+    
+    assert_str("test error message", s_lastLoggedError, "expected 'test error message'");
+
+    log_set_output(NULL); // Reset to default
+}