PowerMock 与 EasyMock，期望返回 null 而不是模拟

Question

寻找一些关于为什么期望返回 null 而不是请求的模拟的指导。有问题的模拟是一个未来，并且遵循与其他正确返回的模拟相同的模式。

为了向具有 powermock 和 easymock 经验的人提供所有信息，我已经包含了所有代码，包括被测代码和设置模拟和行为的测试代码。有问题的期望是

EasyMock.expect( mockAsyncClient.execute( EasyMock.isA( HttpGet.class ),
EasyMOck.isA( HttpClientContext.class ), isNull() ).andReturn( mockFuture )

它产生一个 null 而不是返回一个模拟的 Future。

任何想法都将不胜感激。

附言测试这个功能需要大量的模拟设置，我希望这不会妨碍评估问题。任何删除不必要的模拟基础设施的建议将不胜感激。

这是正在测试的代码

    public <T> T getResponse( ResponseHandler<T> responseHandler )
    throws IOException, InterruptedException, ExecutionException
{
    String connectTo = buildUri();

    try( CloseableHttpAsyncClient httpClient =
                                             HttpAsyncClients.custom()
                                                             .setConnectionManager( connManager )
                                                             .build() ) {
        HttpGet request = new HttpGet( connectTo );
        HttpClientContext ctx = HttpClientContext.create();

        addHeaders( request );

        httpClient.start();

        Future<HttpResponse> futureResponse = httpClient.execute( request, ctx, null ); //<-- this line executes using a verified HttpClient mock but returns null

        HttpResponse response = futureResponse.get();

        return responseHandler.handleResponse( response );
    }
}

测试代码：

    @Test
@PrepareOnlyThisForTest( { HttpAsyncClients.class, HttpAsyncClientBuilder.class } )
public void testGetResponseCallsResponseHandler()
    throws IOException, InterruptedException, ExecutionException
{
    // create mocks to be used when exercising the code under test
    CloseableHttpAsyncClient mockAsyncClient =
                                             EasyMock.createMock( CloseableHttpAsyncClient.class );

    PowerMock.mockStatic( HttpAsyncClients.class );

    HttpAsyncClientBuilder mockClientBuilder =
                                             PowerMock.createMock( HttpAsyncClientBuilder.class );
    HttpAsyncClientBuilder mockClientBuilder2 =
                                              PowerMock.createMock( HttpAsyncClientBuilder.class );

    HttpResponse mockResponse = PowerMock.createMock( HttpResponse.class );
    StatusLine mockStatusLine = PowerMock.createMock( StatusLine.class );
    @SuppressWarnings( "unchecked" )
    Future<HttpResponse> mockFuture = PowerMock.createMock( Future.class );

    // set up expectations that use the mocks
    EasyMock.expect( HttpAsyncClients.custom() ).andReturn( mockClientBuilder );
    EasyMock.expect( mockClientBuilder.setConnectionManager( EasyMock.isA( NHttpClientConnectionManager.class ) ) )
            .andReturn( mockClientBuilder2 );
    EasyMock.expect( mockClientBuilder2.build() ).andReturn( mockAsyncClient );

    mockAsyncClient.start();
    EasyMock.expectLastCall().once();

    EasyMock.expect( mockAsyncClient.execute( EasyMock.isA( HttpGet.class ),
                                              EasyMock.isA( HttpClientContext.class ),
                                              EasyMock.isNull() ) )
            .andReturn( mockFuture );

    EasyMock.expect( mockFuture.get() ).andReturn( mockResponse );

    EasyMock.expect( mockResponse.getStatusLine() ).andReturn( mockStatusLine );
    EasyMock.expect( mockStatusLine.getStatusCode() ).andReturn( 200 );

    mockAsyncClient.close();
    EasyMock.expectLastCall().once();

    PowerMock.replayAll();

    ClientConfig cfg = new ClientConfigBuilder().build();
    RestClient client = new RestClient( cfg );

    int statusCode = client.getResponse( new ResponseHandler<Integer>() {

        @Override
        public Integer handleResponse( HttpResponse response )
            throws ClientProtocolException, IOException
        {
            StatusLine statusLine = response.getStatusLine();
            return statusLine.getStatusCode();
        }

    } );

    PowerMock.verifyAll();

    assertEquals( "status code incorrect", 200, statusCode );
}

Answer 1

我发现了这个问题，而且我确信这是许多其他问题中的问题之一......

返回 null 的模拟可以解释为我错误地使用 EasyMock 而不是 PowerMock 创建模拟：

CloseableHttpAsyncClient mockAsyncClient =
                                         EasyMock.createMock( CloseableHttpAsyncClient.class );

通过将该行更改为

CloseableHttpAsyncClient mockAsyncClient =
                                         PowerMock.createMock( CloseableHttpAsyncClient.class );

测试通过了。

原因是 PowerMock 拥有它用于创建的模拟，并且只能验证这些模拟上的行为。 PowerMock 包装了 EasyMock，因此需要对受控制的模拟进行可见性。

对于受此问题影响的人，请为该问题投票。不知道为什么我被否决了，但请让这个答案更容易被发现。

谢谢，罗宾。

Answer 2

我来到这里是因为我试图 whenNew(SomeClass.class).withAnyArguments() 参加这样的课程：

class SomeClass {
     public SomeClass(String... args) { }
}

原来withAnyArguments() 不匹配可变参数。就我而言，解决方法是：

whenNew(SomeClass.class).withArguments(Matchers.<String>anyVararg()).thenReturn(myMock);