Introduce golden file mechanism for tests

Makefile

@@ -7,6 +7,8 @@ c2: v0/bin/c2
 
 test::
 
+generate_golden::
+
 clean::
 	rm -f c2
 

v0/include.mk

@@ -22,6 +22,9 @@ v0/bin/test: $(V0_SRC_OBJ_NO_MAIN) $(V0_TEST_OBJ)
 test:: v0/bin/test
 	v0/bin/test
 
+generate_golden:: v0/bin/test
+	GENERATE_GOLDEN=1 v0/bin/test
+
 clean::
 	rm -f v0/bin/test v0/bin/c2 $(V0_SRC_OBJ) $(V0_TEST_OBJ) $(V0_SRC_DEPS) $(V0_TEST_DEPS)
 

v0/test.c

@@ -29,6 +29,44 @@ void assert_log(const char* expected, const char* msg) {
     assert_str(expected, s_logOutput, msg);
 }
 
+void assert_log_file(const char* filepath, const char* msg) {
+    const char* generate = getenv("GENERATE_GOLDEN");
+    if (generate && strcmp(generate, "1") == 0) {
+        FILE* f = fopen(filepath, "w");
+        if (!f) {
+            fail("could not open golden file for writing");
+            return;
+        }
+        fputs(s_logOutput ? s_logOutput : "", f);
+        fclose(f);
+        return;
+    }
+
+    FILE* f = fopen(filepath, "r");
+    if (!f) {
+        fail("could not open golden file for reading");
+        return;
+    }
+
+    fseek(f, 0, SEEK_END);
+    long size = ftell(f);
+    fseek(f, 0, SEEK_SET);
+
+    char* content = malloc(size + 1);
+    if (!content) {
+        fclose(f);
+        fail("could not allocate memory for golden file content");
+        return;
+    }
+
+    fread(content, 1, size, f);
+    content[size] = '\0';
+    fclose(f);
+
+    assert_str(content, s_logOutput, msg);
+    free(content);
+}
+
 static void log_append(const char* msg) {
     size_t oldLen = s_logOutput ? strlen(s_logOutput) : 0;
     size_t newLen = oldLen + strlen(msg) + 1;
@@ -75,7 +113,6 @@ static TestCase s_tests[] = {
     {"parser_module_name", test_parser_module_name},
     {"log_error", test_log_error},
     {"log_on_line", test_log_on_line},
-    {"log_on_line_format", test_log_on_line_format},
 };
 
 

v0/test.h

@@ -38,4 +38,10 @@ void assert_str(const char* expected, const char* actual, const char* msg);
  */
 void assert_log(const char* expected, const char* msg);
 
+/**
+ * Asserts that the logged output matches the content of a file.
+ * If GENERATE_GOLDEN=1, the file is overwritten with the actual output.
+ */
+void assert_log_file(const char* filepath, const char* msg);
+
 #endif

v0/test_log.c

@@ -21,23 +21,10 @@ static void test_log_error(void) {
 }
 
 static void test_log_on_line(void) {
-    const char* expected =
-        "--- test.c ---\n"
-        "1| int main() []\n"
-        "              ^^\n"
-        "   unexpected token\n";
-
     log_on_line("test.c", "int main() []", 1, 12, 13, "unexpected token");
-    assert_log(expected, "expected formatted error message");
-}
-
-static void test_log_on_line_format(void) {
-    const char* expected =
-        "--- test.c ---\n"
-        "1| int main() []\n"
-        "              ^^\n"
-        "   unexpected token 'x'\n";
+    assert_log_file("v0/tests/log_on_line.txt", "expected formatted error message");
 
+    log_clear();
     log_on_line("test.c", "int main() []", 1, 12, 13, "unexpected token '%c'", 'x');
-    assert_log(expected, "expected formatted error message with variadic args");
-}
+    assert_log_file("v0/tests/log_on_line_variadic.txt", "expected formatted error message with variadic args");
+}

v0/test_token.c

@@ -86,12 +86,7 @@ static void test_tokenstream_unknown_token(void) {
 
 	if (tokenstream_next(ts).token != TOKEN_UNKNOWN) fail("expected TOKEN_UNKNOWN");
 	
-	assert_log(
-		"--- test.c ---\n"
-        "1| %\n"
-        "   ^\n"
-        "   unexpected token '%'\n",
-		"expected error message for unknown token");
+	assert_log_file("v0/tests/unknown_token.txt", "expected error message for unknown token");
 
 	tokenstream_close(ts);
 }

v0/tests/log_on_line.txt

@@ -0,0 +1,4 @@
+--- test.c ---
+1| int main() []
+              ^^
+   unexpected token

v0/tests/log_on_line_variadic.txt

@@ -0,0 +1,4 @@
+--- test.c ---
+1| int main() []
+              ^^
+   unexpected token 'x'

v0/tests/unknown_token.txt

@@ -0,0 +1,4 @@
+--- test.c ---
+1| %
+   ^
+   unexpected token '%'