How to use shouldScreamWhenExtraInterfacesEmpty method of org.mockitousage.stacktrace.PointingStackTraceToActualInvocationTest class

This could be achieved by PowerMockito framework.

import org.junit.Before;
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(SomeClass.class)
public class SomeClassTest {

    private SomeClass someInstance;

    @Before
    public void setUp() throws Exception {

        someInstance = PowerMockito.spy(new SomeClass());
    }

    @Test
    public void sendRequest() throws Exception {

        String json = "JSON";
        String text = "Some text";
        int messageId = 1;

        PowerMockito.doReturn(true).when(someInstance, "isMethod");
        PowerMockito.doReturn(messageId).when(someInstance, "getMessageId", json);

        someInstance.sendRequest(json, text);

        PowerMockito.verifyPrivate(someInstance).invoke("isMethod");
        PowerMockito.verifyPrivate(someInstance).invoke("getMessageId", json);
        PowerMockito.verifyPrivate(someInstance).invoke("sendMessage", messageId, text);
    }

}

Further reading has led me to try using ArgumentCaptors and the following works, although much more verbose than I would like.

ArgumentCaptor<String> argument = ArgumentCaptor.forClass(String.class);

verify(errors, atLeastOnce()).add(argument.capture(), any(ActionMessage.class));

List<String> values = argument.getAllValues();

assertTrue(values.contains("exception.message"));
assertTrue(values.contains("exception.detail"));

The Slf4j API doesn't provide such a way but Logback provides a simple solution.

You can use ListAppender : a whitebox logback appender where log entries are added in a public List field that we could use to make our assertions.

Here is a simple example.

Foo class :

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

public class Foo {

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

    public void doThat() {
        logger.info("start");
        //...
        logger.info("finish");
    }
}

FooTest class :

import org.slf4j.LoggerFactory;
import ch.qos.logback.classic.Level;
import ch.qos.logback.classic.Logger;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.read.ListAppender;

public class FooTest {

    @Test
    void doThat() throws Exception {
        // get Logback Logger 
        Logger fooLogger = (Logger) LoggerFactory.getLogger(Foo.class);

        // create and start a ListAppender
        ListAppender<ILoggingEvent> listAppender = new ListAppender<>();
        listAppender.start();

        // add the appender to the logger
        fooLogger.addAppender(listAppender);

        // call method under test
        Foo foo = new Foo();
        foo.doThat();

        // JUnit assertions
        List<ILoggingEvent> logsList = listAppender.list;
        assertEquals("start", logsList.get(0)
                                      .getMessage());
        assertEquals(Level.INFO, logsList.get(0)
                                         .getLevel());

        assertEquals("finish", logsList.get(1)
                                       .getMessage());
        assertEquals(Level.INFO, logsList.get(1)
                                         .getLevel());
    }
}

You can also use Matcher/assertion libraries as AssertJ or Hamcrest.

With AssertJ it would be :

import org.assertj.core.api.Assertions;

Assertions.assertThat(listAppender.list)
          .extracting(ILoggingEvent::getFormattedMessage, ILoggingEvent::getLevel)
          .containsExactly(Tuple.tuple("start", Level.INFO), Tuple.tuple("finish", Level.INFO));

Try the anyVararg() matcher. This was introduced in 1.8.1.

Static methods aren't related to any object - your helper.fetchUsernameFromInternet(...) is the same (but a bit confusing) as HelperUtils.fetchUsernameFromInternet(...) - you should even get a compiler warning due to this helper.fetchUsernameFromInternet.

What's more, instead of Mockito.mock to mock static methods you have to use: @RunWith(...), @PrepareForTest(...) and then PowerMockito.mockStatic(...) - complete example is here: PowerMockito mock single static method and return object

In other words - mocking static methods (and also constructors) is a bit tricky. Better solution is:

• if you can change HelperUtils, make that method non-static and now you can mock HelperUtils with the usual Mockito.mock

• if you can't change HelperUtils, create a wrapper class which delegates to the original HelperUtils, but doesn't have static methods, and then also use usual Mockito.mock (this idea is sometimes called "don't mock types you don't own")

Actually org.mockito.Matchers.eq uses org.mockito.internal.matchers.Equality.areEqual(Object o1, Object o2) method to check equality of given matcher to actual value passed to the method. What is interesting, the implementation of this method was stolen from hamcrest as is stated in comment:

//stolen from hamcrest because I didn't want to have more dependency than Matcher class 
//...
public static boolean areEqual(Object o1, Object o2) {
    if (o1 == o2 ) {
        return true;
} else if (o1 == null || o2 == null) {
        return o1 == null && o2 == null;
    } else if (isArray(o1)) {
        return isArray(o2) && areArraysEqual(o1, o2);
    } else {
        return o1.equals(o2);
    }
}

Place a breakpoint at the very beginning of this method to see what is happening in your own code. Since you pass ArrayList to the argument of eq() you may need to dig deeper into areArraysEqual and areArrayLengthsEqual methods.

It is possible for third-party plugins to register custom MockMaker implementations that create classes differently to the default behavior via Mockito's SPI. As a part of the specified behavior, since Mockito 2.0, a MockMaker can decide if a class is mockable, such as final classes in the case of PowerMock. In order to integrate such a custom behavior, PowerMock registers a custom MockMaker that is then used by Mockito.

In Mockito 2.0, the API for a custom MockMaker had to be extended but PowerMock does not yet adapt the API extensions. Therefore, this new method is not yet implemented by the PowerMock MockMaker what results in an AbstractMethodError.

The right thing to do is to restructure your code to make it more testable as shown below. Restructuring your code to remove the direct dependency on Date will allow you to inject different implementations for normal runtime and test runtime:

interface DateTime {
    Date getDate();
}

class DateTimeImpl implements DateTime {
    @Override
    public Date getDate() {
       return new Date();
    }
}

class MyClass {

    private final DateTime dateTime;
    // inject your Mock DateTime when testing other wise inject DateTimeImpl

    public MyClass(final DateTime dateTime) {
        this.dateTime = dateTime;
    }

    public long getDoubleTime(){
        return dateTime.getDate().getTime()*2;
    }
}

public class MyClassTest {
    private MyClass myClassTest;

    @Before
    public void setUp() {
        final Date date = Mockito.mock(Date.class);
        Mockito.when(date.getTime()).thenReturn(30L);

        final DateTime dt = Mockito.mock(DateTime.class);
        Mockito.when(dt.getDate()).thenReturn(date);

        myClassTest = new MyClass(dt);
    }

    @Test
    public void someTest() {
        final long doubleTime = myClassTest.getDoubleTime();
        assertEquals(60, doubleTime);
    }
}

As you pointed out, it is not possible to mock static methods with Mockito and since you do not wanna use Powermock or other tools, you can try something as follows in your tests.

1. Create test authentication object

   Authentication auth = new ... // create instance based on your needs and with required attributes or just mock it if you do not care

2. Mock security context

   SecurityContext context = mock(SecurityContext.class);

3. Ensure your mock returns the respective authentication

   when(context.getAuthentication()).thenReturn(auth);

4. Set security context into holder

   SecurityContextHolder.setContext(securityContext);

Now every call to SecurityContextHolder.getContext().getAuthentication() should return authentication object created in step 1.