fix: resolve cppcheck warnings in new test files

- Remove unused ConsumerCtx struct in test_stress.c
- Add const qualifiers to variables only checked for NULL
  in test_metadata.c, test_protocol.c, test_robustness.c

tests/test_metadata.c

@@ -55,7 +55,7 @@ static void test_metadata_from_buf_null() {
   memcpy(buf, &present, sizeof(int));
 
   char* read_ptr = buf;
-  FileMetadata* result = metadata_from_buf(&read_ptr);
+  const FileMetadata* result = metadata_from_buf(&read_ptr);
 
   EXPECT_NULL(result);
 
@@ -101,7 +101,7 @@ static void test_metadata_send_null() {
   EXPECT_TRUE(metadata_send(p[1], NULL));
 
   int ok = 0;
-  FileMetadata* received = metadata_receive(p[0], &ok);
+  const FileMetadata* received = metadata_receive(p[0], &ok);
   EXPECT_NULL(received);
   EXPECT_EQ_INT(ok, 1);
 

tests/test_protocol.c

@@ -163,7 +163,7 @@ static void test_receive_str_truncated() {
   io_set_bwlimit(0);
   close(p[1]);
 
-  char* received = receive_str(0);
+  const char* received = receive_str(0);
   EXPECT_NULL(received);
 
   close(p[0]);

tests/test_robustness.c

@@ -30,7 +30,7 @@ static void test_chunk_deserialize_truncated() {
   size_t orig_size = serialized->size;
   serialized->size = orig_size / 2;
 
-  Chunk* result = chunk_deserialize(serialized, false);
+  const Chunk* result = chunk_deserialize(serialized, false);
   EXPECT_NULL(result);
 
   serialized->size = orig_size;
@@ -45,7 +45,7 @@ static void test_chunk_deserialize_empty() {
   EXPECT_NOT_NULL(d);
   memcpy(d->data, garbage, sizeof(garbage));
 
-  Chunk* result = chunk_deserialize(d, false);
+  const Chunk* result = chunk_deserialize(d, false);
   EXPECT_NULL(result);
 
   data_destroy(d);
@@ -57,7 +57,7 @@ static void test_chunk_deserialize_garbage() {
   EXPECT_NOT_NULL(d);
   memcpy(d->data, garbage, sizeof(garbage));
 
-  Chunk* result = chunk_deserialize(d, false);
+  const Chunk* result = chunk_deserialize(d, false);
   EXPECT_NULL(result);
 
   data_destroy(d);
@@ -77,7 +77,7 @@ static void test_delta_deserialize_truncated() {
   EXPECT_NOT_NULL(serialized);
 
   serialized->size = 4;
-  Delta* result = delta_deserialize(serialized);
+  const Delta* result = delta_deserialize(serialized);
   EXPECT_NULL(result);
 
   data_destroy(serialized);
@@ -91,7 +91,7 @@ static void test_delta_deserialize_empty() {
   EXPECT_NOT_NULL(d);
   memcpy(d->data, garbage, sizeof(garbage));
 
-  Delta* result = delta_deserialize(d);
+  const Delta* result = delta_deserialize(d);
   EXPECT_NULL(result);
 
   data_destroy(d);
@@ -103,7 +103,7 @@ static void test_delta_deserialize_garbage() {
   EXPECT_NOT_NULL(d);
   memcpy(d->data, garbage, sizeof(garbage));
 
-  Delta* result = delta_deserialize(d);
+  const Delta* result = delta_deserialize(d);
   EXPECT_NULL(result);
 
   data_destroy(d);
@@ -119,7 +119,7 @@ static void test_delta_signature_deserialize_truncated() {
   EXPECT_NOT_NULL(serialized);
 
   serialized->size = 4;
-  DeltaSignature* result = delta_signature_deserialize(serialized);
+  const DeltaSignature* result = delta_signature_deserialize(serialized);
   EXPECT_NULL(result);
 
   data_destroy(serialized);
@@ -127,7 +127,7 @@ static void test_delta_signature_deserialize_truncated() {
 }
 
 static void test_delta_apply_null() {
-  void* result = delta_apply(NULL, 0, NULL, 0);
+  const void* result = delta_apply(NULL, 0, NULL, 0);
   EXPECT_NULL(result);
 }
 
@@ -151,7 +151,7 @@ static void test_receive_data_closed_pipe() {
   io_set_bwlimit(0);
   close(p[1]);
 
-  Data* result = receive_data(0);
+  const Data* result = receive_data(0);
   EXPECT_NULL(result);
 
   close(p[0]);
@@ -164,7 +164,7 @@ static void test_receive_str_closed_pipe() {
   io_set_bwlimit(0);
   close(p[1]);
 
-  char* result = receive_str(0);
+  const char* result = receive_str(0);
   EXPECT_NULL(result);
 
   close(p[0]);

tests/test_stress.c

@@ -19,15 +19,6 @@ typedef struct {
   int producer_id;
 } ProducerCtx;
 
-typedef struct {
-  Queue* q;
-  mtx_t* mutex;
-  cnd_t* cnd_empty;
-  cnd_t* cnd_full;
-  volatile bool* done;
-  int sum;
-} ConsumerCtx;
-
 typedef struct {
   Queue* q;
   mtx_t* mutex;