refactor: unit test

src/mito2/src/cache/write_cache.rs

@@ -167,8 +167,7 @@ mod tests {
         let cache = FileCache::new(local_store.clone(), ReadableSize::mb(10));
         let file_id = FileId::random();
 
-        // Create Env
-        let mut env = TestEnv::new();
+        // Create Source
         let metadata = Arc::new(sst_region_metadata());
         let region_id = metadata.region_id;
         let source = new_source(&[
@@ -177,13 +176,19 @@ mod tests {
             new_batch_by_range(&["b", "h"], 100, 200),
         ]);
 
-        // Another fs store to mock uploading
+        // Because we couldn't create a S3 object store in unit test,
+        // use another Fs store to mock uploading place.
+        let mut env = TestEnv::new();
         let mock_store = env.init_object_store_manager();
         let upload_path = sst_file_path("test", file_id);
 
-        // Create write cache
+        // Create WriteCache
         let object_store_manager = Arc::new(ObjectStoreManager::new("mock", mock_store.clone()));
-        let write_cache = WriteCache::new(local_store, object_store_manager, ReadableSize::mb(10));
+        let write_cache = WriteCache::new(
+            local_store.clone(),
+            object_store_manager,
+            ReadableSize::mb(10),
+        );
 
         let request = SstUploadRequest {
             file_id,
@@ -210,11 +215,12 @@ mod tests {
         let key = (region_id, file_id);
         assert!(write_cache.file_cache.contains_key(&key));
 
-        // Check the file size
-        let file_size = sst_info.file_size;
+        // Check file
         // Read from mock remote store
-        let n: usize = mock_store.read(&upload_path).await.unwrap().len();
-        assert_eq!(file_size, n as u64);
+        let remote_data = mock_store.read(&upload_path).await.unwrap();
+        // Read from local file cache
+        let cache_data = local_store.read(&cache.cache_file_path(key)).await.unwrap();
+        assert_eq!(remote_data, cache_data);
 
         // Delete test files
         mock_store.delete(&upload_path).await;