我写了一个工厂来产生java.sql.Connection对象:

public class MySQLDatabaseConnectionFactory implements DatabaseConnectionFactory {

    @Override public Connection getConnection() {
        try {
            return DriverManager.getConnection(...);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }
}

我想验证传递给DriverManager的参数。getConnection,但我不知道如何模拟静态方法。我的测试用例使用JUnit 4和Mockito。是否有一个好的方法来模拟/验证这个特定的用例?


当前回答

观察:当您在静态实体中调用静态方法时,您需要更改@PrepareForTest中的类。

例如:

securityAlgo = MessageDigest.getInstance(SECURITY_ALGORITHM);

对于上面的代码,如果您需要模拟MessageDigest类,请使用

@PrepareForTest(MessageDigest.class)

而如果你有如下内容:

public class CustomObjectRule {

    object = DatatypeConverter.printHexBinary(MessageDigest.getInstance(SECURITY_ALGORITHM)
             .digest(message.getBytes(ENCODING)));

}

然后,您需要准备这个代码所在的类。

@PrepareForTest(CustomObjectRule.class)

然后模拟这个方法:

PowerMockito.mockStatic(MessageDigest.class);
PowerMockito.when(MessageDigest.getInstance(Mockito.anyString()))
      .thenThrow(new RuntimeException());

其他回答

观察:当您在静态实体中调用静态方法时,您需要更改@PrepareForTest中的类。

例如:

securityAlgo = MessageDigest.getInstance(SECURITY_ALGORITHM);

对于上面的代码,如果您需要模拟MessageDigest类,请使用

@PrepareForTest(MessageDigest.class)

而如果你有如下内容:

public class CustomObjectRule {

    object = DatatypeConverter.printHexBinary(MessageDigest.getInstance(SECURITY_ALGORITHM)
             .digest(message.getBytes(ENCODING)));

}

然后,您需要准备这个代码所在的类。

@PrepareForTest(CustomObjectRule.class)

然后模拟这个方法:

PowerMockito.mockStatic(MessageDigest.class);
PowerMockito.when(MessageDigest.getInstance(Mockito.anyString()))
      .thenThrow(new RuntimeException());

在Mockito之上使用PowerMockito。

示例代码:

@RunWith(PowerMockRunner.class)
@PrepareForTest(DriverManager.class)
public class Mocker {

    @Test
    public void shouldVerifyParameters() throws Exception {

        //given
        PowerMockito.mockStatic(DriverManager.class);
        BDDMockito.given(DriverManager.getConnection(...)).willReturn(...);

        //when
        sut.execute(); // System Under Test (sut)

        //then
        PowerMockito.verifyStatic();
        DriverManager.getConnection(...);

    }

更多信息:

为什么Mockito不模拟静态方法?

稍微重构一下:

public class MySQLDatabaseConnectionFactory implements DatabaseConnectionFactory {
    ConnectionSupplier connectionSupplier = () -> SupplierDriverManager.getConnection();

    public void setConnSupplier(ConnectionSupplier supplier) {
        this.connectionSupplier = supplier;
    }

    @Override 
    public Connection getConnection() {
        try {
            return connectionSupplier.conn();
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }
    @FunctionalInterface
    interface ConnectionSupplier {
        Connection conn();
    }
}

然后你可以使用mockito:

MySQLDatabaseConnectionFactory.ConnectionSupplier connectionSupplier = mock(MySQLDatabaseConnectionFactory.ConnectionSupplier.class);
when(connectionSupplier.conn()).thenReturn(yourMockObject);
yourConnectionFactory.setConnSupplier(connectionSupplier);

我在《Mockito》中找到了一个解决方法。该特性仅在3.4.0版本中提供

https://asolntsev.github.io/en/2020/07/11/mockito-static-methods/

dependency In your build.gradle replace mockito-core:3.3.3 by mockito-inline:3.4.0: testImplementation('org.mockito:mockito-inline:3.4.0') what are we going to mock class Buddy { static String name() { return "John"; } } Mock the static method @Test void lookMomICanMockStaticMethods() { assertThat(Buddy.name()).isEqualTo("John"); try (MockedStatic<Buddy> theMock = Mockito.mockStatic(Buddy.class)) { theMock.when(Buddy::name).thenReturn("Rafael"); assertThat(Buddy.name()).isEqualTo("Rafael"); } assertThat(Buddy.name()).isEqualTo("John"); }

我想这对我们有帮助。

我也遇到过类似的问题。根据PowerMock的mockStatic文档,接受的答案对我不起作用,直到我做出了更改:@PrepareForTest(classthatcontainsstaticmethod .class)。

我不需要使用BDDMockito。

我的类:

public class SmokeRouteBuilder {
    public static String smokeMessageId() {
        try {
            return InetAddress.getLocalHost().getHostAddress();
        } catch (UnknownHostException e) {
            log.error("Exception occurred while fetching localhost address", e);
            return UUID.randomUUID().toString();
        }
    }
}

我的测试类:

@RunWith(PowerMockRunner.class)
@PrepareForTest(SmokeRouteBuilder.class)
public class SmokeRouteBuilderTest {
    @Test
    public void testSmokeMessageId_exception() throws UnknownHostException {
        UUID id = UUID.randomUUID();

        mockStatic(InetAddress.class);
        mockStatic(UUID.class);
        when(InetAddress.getLocalHost()).thenThrow(UnknownHostException.class);
        when(UUID.randomUUID()).thenReturn(id);

        assertEquals(id.toString(), SmokeRouteBuilder.smokeMessageId());
    }
}