added unit test

Author: Fred1155

services/s3/src/test/java/software/amazon/awssdk/services/s3/internal/multipart/MultipartDownloaderSubscriberMockClientTest.java

@@ -0,0 +1,123 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.awssdk.services.s3.internal.multipart;
+
+
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.when;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.reactivestreams.Subscription;
+import software.amazon.awssdk.core.async.AsyncResponseTransformer;
+import software.amazon.awssdk.core.exception.SdkClientException;
+import software.amazon.awssdk.services.s3.S3AsyncClient;
+import software.amazon.awssdk.services.s3.model.GetObjectRequest;
+import software.amazon.awssdk.services.s3.model.GetObjectResponse;
+
+public class MultipartDownloaderSubscriberMockClientTest {
+    @Mock
+    private S3AsyncClient s3Client;
+
+    @Mock
+    private Subscription subscription;
+
+    @Mock
+    private AsyncResponseTransformer<GetObjectResponse, GetObjectResponse> responseTransformer;
+
+    private GetObjectRequest getObjectRequest;
+    private MultipartDownloaderSubscriber subscriber;
+
+    @BeforeEach
+    void setUp() {
+        MockitoAnnotations.openMocks(this);
+        getObjectRequest = GetObjectRequest.builder()
+                                           .bucket("test-bucket")
+                                           .key("test-key")
+                                           .build();
+    }
+
+    @Test
+    void testValidationPassesWhenCallCountMatchesTotalParts() throws InterruptedException {
+        subscriber = new MultipartDownloaderSubscriber(s3Client, getObjectRequest);
+        GetObjectResponse response1 = createMockResponse(3, "etag1");
+        GetObjectResponse response2 = createMockResponse(3, "etag2");
+        GetObjectResponse response3 = createMockResponse(3, "etag3");
+
+        CompletableFuture<GetObjectResponse> future1 = CompletableFuture.completedFuture(response1);
+        CompletableFuture<GetObjectResponse> future2 = CompletableFuture.completedFuture(response2);
+        CompletableFuture<GetObjectResponse> future3 = CompletableFuture.completedFuture(response3);
+
+        when(s3Client.getObject(any(GetObjectRequest.class), eq(responseTransformer)))
+            .thenReturn(future1, future2, future3);
+
+        subscriber.onSubscribe(subscription);
+        subscriber.onNext(responseTransformer);
+        subscriber.onNext(responseTransformer);
+        subscriber.onNext(responseTransformer);
+        Thread.sleep(100);
+
+        subscriber.onComplete();
+
+        assertDoesNotThrow(() -> subscriber.future().get(1, TimeUnit.SECONDS));
+    }
+
+    @Test
+    void testValidationFailsWhenCallCountExceedsTotalParts() throws InterruptedException {
+        subscriber = new MultipartDownloaderSubscriber(s3Client, getObjectRequest);
+        GetObjectResponse response1 = createMockResponse(3, "etag1");
+        GetObjectResponse response2 = createMockResponse(3, "etag2");
+
+        CompletableFuture<GetObjectResponse> future1 = CompletableFuture.completedFuture(response1);
+        CompletableFuture<GetObjectResponse> future2 = CompletableFuture.completedFuture(response2);
+
+        when(s3Client.getObject(any(GetObjectRequest.class), eq(responseTransformer)))
+            .thenReturn(future1, future2);
+
+        subscriber.onSubscribe(subscription);
+        subscriber.onNext(responseTransformer);
+        subscriber.onNext(responseTransformer);
+        Thread.sleep(100);
+
+        subscriber.onComplete();
+
+        ExecutionException exception = assertThrows(ExecutionException.class,
+                                                    () -> subscriber.future().get(1, TimeUnit.SECONDS));
+        assertTrue(exception.getCause() instanceof SdkClientException);
+        assertTrue(exception.getCause().getMessage().contains("PartsCount validation failed"));
+        assertTrue(exception.getCause().getMessage().contains("Expected 3, downloaded 2 parts"));
+
+    }
+
+    private GetObjectResponse createMockResponse(int partsCount, String etag) {
+        GetObjectResponse.Builder builder = GetObjectResponse.builder()
+                                                             .eTag(etag)
+                                                             .contentLength(1024L);
+
+        builder.partsCount(partsCount);
+        return builder.build();
+    }
+
+}