我想模拟一个扩展 InputStream、模拟读取、验证关闭的专有类

Question

我想使用 Mockito 来模拟 AmazonS3 并测试从中打开一个流，然后在我的代码读取它后验证该流是否已关闭。我还想从流中读取字节。像这样的东西：

    AmazonS3 client = mock(AmazonS3.class);
        when(tm.getAmazonS3Client()).thenReturn(client);
        S3Object response = mock(S3Object.class); 
        when(client.getObject(any(GetObjectRequest.class))).thenReturn(response);
        S3ObjectInputStream stream = mock(S3ObjectInputStream.class); 
        when(response.getObjectContent()).thenReturn(stream);

somehow mock the read method

MyObject me = new MyObject(client);
byte[] bra me.getBytes(File f, offset, length);
assertEquals(length, bra.length);
verify(stream).close();

Answer 1

您可以使用 Mockito 的答案来模拟流。

    String expectedContents = "Some contents";
    InputStream testInputStream = new StringInputStream(expectedContents);
    S3ObjectInputStream s3ObjectInputStream = mock(S3ObjectInputStream.class);
    S3Object s3Object = mock(S3Object.class);
    AmazonS3Client amazonS3Client = mock(AmazonS3Client.class);
    S3AttachmentsService service = new S3AttachmentsService(amazonS3Client);

    when(s3ObjectInputStream.read(any(byte[].class))).thenAnswer(invocation -> {
        return testInputStream.read(invocation.getArgument(0));
    });

我这里有一个更广泛的例子。希望有帮助。