PowerMockito.mockStatic(class) simulate static method call

Why write unit tests

1. give us the confidence to refactor. A bunch of tangled and untested code, do you dare to modify it?
2. A good unit test is a document expected behavior. A few practical examples are more interesting than documents!

Introduce dependency

        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-core</artifactId>
            <version>2.23.4</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.powermock</groupId>
            <artifactId>powermock-api-mockito2</artifactId>
            <version>2.0.0</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.powermock</groupId>
            <artifactId>powermock-module-junit4</artifactId>
            <version>2.0.0</version>
            <scope>test</scope>
        </dependency>

Simulation tool class calls static methods

Tool class: SysDataCodeUtils

@Slf4j
public class SysDataCodeUtils {
    public static String getNameByCodeAndValue(String code, String key) {
        try {
            List<SysDataCodeDTO> list = sysDataCodeService.getListByCode(code);
            for (SysDataCodeDTO dataCodeDTO : list) {
                if (dataCodeDTO.getCode().equals(key)) {
                    return dataCodeDTO.getValue();
                }
            }
        } catch (Exception e) {
            log.error("Get quick code table exception:{}", e);
        }
        return StrUtil.EMPTY;
    }
}

Test class: ShareProfitRefundSettleServiceImplTest

@RunWith(PowerMockRunner.class)
@PrepareForTest({ SysDataCodeUtils.class })
public class ShareProfitRefundSettleServiceImplTest {

    @InjectMocks
    ShareProfitRefundSettleServiceImpl shareProfitRefundSettleService = new ShareProfitRefundSettleServiceImpl();

    @Mock
    ClearingDao clearingDao;

    @Before
    public void before(){
        log.info("start--------{}",this.getClass().getName());
        
        PowerMockito.mockStatic(SysDataCodeUtils.class);
        PowerMockito.when(SysDataCodeUtils.getNameByCodeAndValue("SHARE_PROFIT_REFUND_TERM", "SWITCH")).thenReturn("OPEN");
        
    }
}

Notes

@RunWith( MockitoJUnitRunner.class ): JUnit uses the "unit test runner" provided by the Mockito simulation framework.

@RunWith( PowerMockRunner.class ): JUnit uses the unit test runner in the PowerMock framework.
The point of using these framework specific test runners is that they are responsible for initializing all fields with special framework specific comments.

@PrepareForTest({ SysDataCodeUtils.class }): when using PowerMockito.whenNew Method must be annotated with @ preparefortest and @ RunWith. The class written in the annotation @ preparefortest is the class where the new object code requiring mock is located. If there are two different static methods to verify, such as class A and class B, you only need to add them together and separate them with commas: @ preparefortest ({a.class, b.class}).

@InjectMocks: create an instance. In short, this mocks can call methods of real code. The rest mocks created with @ mocks (or @ Spy) annotation will be injected into this instance.

@Mock: create a mock.