Mock private static final field using mockito or Jmockit

Question

I am using private static final LOGGER field in my class and I want LOGGER.isInfoEnabled() method to return false. How can I mock the static final field by using mockito or jMockit

My class is:

  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;

  public class Class1 {

  private static final Logger LOGGER = LoggerFactory.getLogger(Class1.class);

    public boolean demoMethod() {
       System.out.println("Demo started");
       if (LOGGER.isInfoEnabled()) {
         System.out.println("@@@@@@@@@@@@@@ ------- info is enabled");
       } else {
         System.out.println("info is disabled");
       }
       return LOGGER.isInfoEnabled();
    }
  }

and its junit is :

import mockit.Mocked;
import mockit.NonStrictExpectations;
import org.mockito.InjectMocks;
import org.mockito.MockitoAnnotations;
import org.slf4j.Logger;
import org.testng.annotations.BeforeMethod;
import org.testng.annotations.Test;

import static org.testng.Assert.*;
import com.source.Class1;

public class MyTest {

  @InjectMocks
  Class1 cls1;

  @BeforeMethod
  public void initMocks() {
    MockitoAnnotations.initMocks(this);
  }

  @Test
  public void test(@Mocked final Logger LOGGER) {

    new NonStrictExpectations() {
      {
        LOGGER.isInfoEnabled();
        result = false;
      }
    };
    assertFalse(cls1.demoMethod());
  }
}

when I run it the result is:

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.test.MyTest
Configuring TestNG with: TestNG652Configurator
Demo started
@@@@@@@@@@@@@@ ------- info is enabled
Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 1.9 sec <<< FAILURE! - in com.test.MyTest
test(com.test.MyTest)  Time elapsed: 0.168 sec  <<< FAILURE!
java.lang.AssertionError: expected [false] but found [true]
        at com.test.MyTest.test(MyTest.java:35)


Results :

Failed tests:
  MyTest.test:35 expected [false] but found [true]

Tests run: 1, Failures: 1, Errors: 0, Skipped: 0

[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 9.899s
[INFO] Finished at: Mon Jun 08 12:35:36 IST 2015
[INFO] Final Memory: 16M/166M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.18.1:test (default-test) on project JMockDemo: The
re are test failures.
[ERROR]
[ERROR] Please refer to D:\perfoce_code\workspace_kepler\JMockDemo\target\surefire-reports for the individual test results.
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

I am new to jmockit and I want my above junit case to run successfully. And I have to use JMockit or mockito, can't use Powermockito. Please help.

Answer 1

One way is using reflection get rid of final modifier from the field and then replace the LOGGER field with Mocked one

public class Class1Test {
    @Test
    public void test() throws Exception {
        Logger logger = Mockito.mock(Logger.class);
        Mockito.when(logger.isInfoEnabled()).thenReturn(false);
        setFinalStatic(Class1.class.getDeclaredField("LOGGER"), logger);
        Class1 cls1 = new Class1();
        assertFalse(cls1.demoMethod());
    }

    static void setFinalStatic(Field field, Object newValue) throws Exception {
        field.setAccessible(true);        
        Field modifiersField = Field.class.getDeclaredField("modifiers");
        modifiersField.setAccessible(true);
        modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);
        field.set(null, newValue);
    }
}

Answer 2

I think mockito or jMockit cant mock static final classes as they try to override the methods while unit testing. However, powerMockito can as it uses Reflection and mocks the static final class/methods.

Answer 3

Changing "@Mocked Logger" to "@Capturing Logger" in the parameter makes it work. like

  @Test
  public void test(@Capturing final Logger LOGGER) {

    new NonStrictExpectations() {
      {
        LOGGER.isInfoEnabled();
        result = false;
      }
    };
    assertFalse(cls1.demoMethod());
  }