java - PowerMock Mockito 方法中的模拟类构造函数

Question

我在尝试使用 PowerMock 模拟类时遇到问题。首先，这是我当前的 gradle 依赖项:

testCompile group: 'junit', name: 'junit', version: '4.12'
testCompile "org.mockito:mockito-core:2.+"
testCompile group: 'org.powermock', name: 'powermock-module-junit4', version: '2.0.2'
testCompile group: 'org.powermock', name: 'powermock-api-mockito2', version: '2.0.2'

我正在尝试模拟对 kafka 经纪人的调用。代码看起来像这样:

public class MyConsumer {
    public Consumer<Long, String> createConsumer() {
        ...
        Consumer<Long, String> consumer = new KafkaConsumer<>(props);
        consumer.subscribe(TOPIC);
        ....
    }
}

createConsumer 中的这两行这就是我试图 mock 的一切。我的测试看起来像这样:

@RunWith(PowerMockRunner.class)
@PrepareForTest(MyConsumer.class)
public class MyConsumerTest {

    @Test
    public void testCreateConsumer() {
        ...
        KafkaConsumer mockConsumer = mock(KafkaConsumer.class);
        doNothing().when(mockConsumer).subscribe(TOPIC);
        PowerMockito.whenNew(KafkaConsumer.class).withAnyArguments().thenReturn(mockConsumer);

        Consumer<Long, String> result = myConsumerInstance.createConsumer();
        ...
    }
}

当我尝试运行测试时，它们从未开始，并且出现此错误:

> Task :compileTestJava FAILED
/Users/myuser/myproject/src/test/java/myConsumerTest.java:101: error: unreported exception Exception; must be caught or declared to be thrown
       PowerMockito.whenNew(KafkaConsumer.class).withAnyArguments().thenReturn(mockConsumer);
                                                                 ^
Note: /Users/myuser/myproject/src/test/java/myConsumerTest.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: /Users/myuser/myproject/src/test/java/myConsumerTest.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
1 error

FAILURE: Build failed with an exception.

所以我想我应该将这行代码换行，以尝试获取有关问题所在的更多信息。当我这样做时，测试运行了，但是该特定测试将失败并给出以下错误:

Kafka.analyticsConsumerTest > testCreateConsumer FAILED
    java.lang.RuntimeException at PowerMockTestNotifierImpl.java:84
        Caused by: org.mockito.exceptions.base.MockitoException at MethodRoadie.java:87

我一生都没弄清楚如何从中提取更多信息。有人遇到过类似的事情吗？

我当前的工作理论与 KafkaConsumer 类如何返回消费者有关？本例中的消费者是 org.apache.kafka.clients.consumer.Consumer 。也许我没有正确地 mock 这一点？任何帮助将不胜感激。

Answer 1

Thanks for the suggestion, but if you reread above, I already did that. That is how I got the Runtime exception to appear. Unless I am misunderstanding what you mean?

也许你这边缺少什么？检查下面的示例，它对我有用。

Gradle :

dependencies {

    testCompile group: 'junit', name: 'junit', version: '4.12'
    testCompile "org.mockito:mockito-core:2.+"
    testCompile group: 'org.powermock', name: 'powermock-module-junit4', version: '2.0.2'
    testCompile group: 'org.powermock', name: 'powermock-api-mockito2', version: '2.0.2'

    compile group: 'org.apache.kafka', name: 'kafka-clients', version: '2.4.0'
}

单元测试:

import java.util.Arrays;
import java.util.Collection;
import java.util.Properties;

import org.apache.kafka.clients.consumer.Consumer;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

@RunWith(PowerMockRunner.class)
@PrepareForTest(MyConsumerTest.MyConsumer.class)
public class MyConsumerTest {

    private static final Collection<String> TOPIC = Arrays.asList("1");

    static class MyConsumer {

        public Consumer<Long, String> createConsumer() {

            Properties props = new Properties();
            Consumer<Long, String> consumer = new KafkaConsumer<>(props);
            consumer.subscribe(TOPIC);

            return consumer;
        }
    }

    @Test
    public void testCreateConsumer() throws Exception {

        KafkaConsumer<?,?> mockConsumer = PowerMockito.mock(KafkaConsumer.class);
        PowerMockito.doNothing().when(mockConsumer).subscribe(TOPIC); // default behaviour, line is not required
        PowerMockito.whenNew(KafkaConsumer.class).withAnyArguments().thenReturn(mockConsumer);

        MyConsumer myConsumerInstance = new MyConsumer();
        Consumer<Long, String> result = myConsumerInstance.createConsumer();

    }
}