EasyMock AssertionError when invoking Logger.error(String, Throwable) - log4j

Question

I am seeing assertion error when I include a Throwable while invoking Log4j.error method. I do have Logger.class, PrintWriter.class, AuthenticationException.class in the #PreparateForTest block. I do not see the error if I do not pass the Throwable as an argument.
What am I missing in setting up mocks correctly?
Caused by: java.lang.AssertionError:
Unexpected method call AuthenticationException.printStackTrace(java.io.PrintWriter#2c64e8ad):
at org.junit.Assert.fail(Assert.java:93)
at com.xxx.yy.security.client.ClientTest.authenticateFail(ClientTest.java:282)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.junit.internal.runners.TestMethod.invoke(TestMethod.java:66)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:310)
... 23 more
JUnit test code snippet is as below:
AuthenticationException mockAuthException = PowerMock
.createMock(AuthenticationException.class);
PrintWriter mockPrintWriter = PowerMock
.createMock(PrintWriter.class);
Logger mockLogger = PowerMock.createMock(Logger.class);
String message = "blah";
mockLogger.error(message, mockAuthException);
EasyMock.expectLastCall();
mockAuthException.printStackTrace(mockPrintWriter);
EasyMock.expectLastCall();
Code snippet that is causing the issue is as below:
try{
.
.
}catch (AuthenticationException ex) {
LOGGER.error("SOME MESSAGE HERE", ex);
throw ex;
}

Answer 1

you are getting an Unexpected method call error which can be solved as follows:
AuthenticationException mockAuthException = EasyMock.createNiceMock(AuthenticationException.class);
PrintWriter mockPrintWriter = EasyMock.createNiceMock(PrintWriter.class);
Logger mockLogger = EasyMock.createNiceMock(Logger.class);
String message = "blah";
mockLogger.error(message, mockAuthException);
EasyMock.expectLastCall();
mockAuthException.printStackTrace(mockPrintWriter);
EasyMock.expectLastCall();
The changes over here are using easymock instead of powermock,and creating a niceMock instead of normal mock.
The createMock(..) method is strict and can not identify if a method is internally called or not,but when you use createNiceMock(..) this check is ignored and you do not get a UnexpectedMethodCall error
Hope it helps!
Good luck!

Answer 2

LOGGER.error("SOME MESSAGE HERE", ex);
This line appears to be calling the printStacktrace method of the ex, i.e the AuthenticationException type. Since you've mocked it, you have to tell the behavior the object (the mock, technically) should behave in, when this call is encountered.
You have 3 choices, apart from relaxing the verification of course thru the use of nice mocks, assuming you really expect this exception to be thrown (your question is a bit vague about it):
See if you can expect the LOGGER.error("SOME MESSAGE HERE", ex);, i.e mock the LOGGER. The LOGGER appears to be a static variable, but you seem to be using Powermock, so I don't think you'll have any problems mocking it, but if you do have concerns mocking the LOGGER, read on
Tell Easymock how it's supposed to respond when it encounters the printStacktrace method call on the mock object mockAuthException by placing an expectation on it like this (printStacktrace being a void method) before you replay the mock:
mockAuthException.printStacktrace(); expectLastCall().andDoSomethingIfNeeded();
Don't mock the AuthenticationException type at all unless it's absolutely necessary - it does look like you can do without mocking it, say, by creating a Stub of the type.