Mockito中ArgumentCaptor捕获泛型参数的实践指南

import org.junit.jupiter.api.Test;
import org.mockito.ArgumentCaptor;

import java.util.function.Consumer;

import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.verify;

// 假设我们有一个被测试的Service，其方法接受 Consumer<String>
class MyService {
    public void process(Consumer<String> consumer) {
        // 实际业务逻辑中可能会调用 consumer.accept("some_data");
        // 这里仅作示例
    }
}

public class MyServiceTest {

    @Test
    void testProcessMethodCapturesConsumerUsingRawType() {
        // 模拟MyService实例，以便验证其方法调用
        MyService mockService = mock(MyService.class);

        // 声明并初始化ArgumentCaptor
        // 使用原始类型Consumer.class，并抑制未经检查的警告
        @SuppressWarnings("unchecked")
        ArgumentCaptor<Consumer<String>> captor = ArgumentCaptor.forClass(Consumer.class);

        // 调用被测方法，并传入一个Consumer实例
        // 实际应用中，这个Consumer可能是由其他组件提供或在内部创建
        mockService.process(s -> System.out.println("Processing: " + s));

        // 验证mockService的process方法被调用，并捕获传递的Consumer参数
        verify(mockService).process(captor.capture());

        // 获取捕获到的Consumer实例
        Consumer<String> capturedConsumer = captor.getValue();

        // 对捕获到的Consumer进行验证
        assertNotNull(capturedConsumer);
        // 例如，可以验证其行为，如果它是一个mock对象
        // capturedConsumer.accept("test");
        // verify(someMockedConsumer).accept("test");
    }
}

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.mockito.ArgumentCaptor;
import org.mockito.Captor;
import org.mockito.MockitoAnnotations;

import java.util.function.Consumer;

import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.verify;

public class MyServiceTest {

    // 声明并使用@Captor注解，Mockito会自动初始化它
    @Captor
    ArgumentCaptor<Consumer<String>> consumerCaptor;

    @BeforeEach
    void setUp() {
        // 初始化所有@Mock, @Spy, @Captor等注解
        MockitoAnnotations.openMocks(this);
    }

    @Test
    void testProcessMethodCapturesConsumerWithCaptor() {
        MyService mockService = mock(MyService.class);

        // 调用一个接受 Consumer 的方法
        mockService.process(s -> System.out.println("Processing: " + s));

        // 捕获传递给 mockService.process 方法的 Consumer 参数
        verify(mockService).process(consumerCaptor.capture());

        // 获取捕获到的Consumer实例
        Consumer<String> capturedConsumer = consumerCaptor.getValue();

        assertNotNull(capturedConsumer);
        // 进一步验证 capturedConsumer 的行为或类型
    }
}

import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.ArgumentCaptor;
import org.mockito.Captor;
import org.mockito.junit.jupiter.MockitoExtension;

import java.util.function.Consumer;

import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.verify;

// 启用Mockito JUnit 5扩展，它会自动处理@Mock, @Spy, @Captor等注解
@ExtendWith(MockitoExtension.class)
public class MyServiceTest {

    @Captor
    ArgumentCaptor<Consumer<String>> consumerCaptor;

    @Test
    void testProcessMethodCapturesConsumerWithMockitoExtension() {
        MyService mockService = mock(MyService.class);

        mockService.process(s -> System.out.println("Processing: " + s));

        verify(mockService).process(consumerCaptor.capture());

        Consumer<String> capturedConsumer = consumerCaptor.getValue();

        assertNotNull(capturedConsumer);
    }
}