How can i make use of mockito to resolve a null pointer exception in my test junit method which are concerned with license of a plugin?

Question

I mock ThirdPartyPluginLicenseStorageManager and PluginLicense.class using mockito in a junit test.

But while calling the internal methods of them it throws null pointer exception.

How can i overcome them as i dont see a way of setting the values in the mock confluence license objects

Few lines in my macro stub

@Mock
private ThirdPartyPluginLicenseStorageManager licenseManager;

@Before
public void setUp() throws Exception {
   super.setUp();
   exampleMacro = new Macro(licenseManager);
   PluginLicense pluginLicense = Mockito.mock(PluginLicense.class);
}

@Test
public void test() throws Exception {

when(pluginLicense.getError().isDefined()).thenReturn(Boolean.FALSE); // Null pointer Exception
   when(licenseManager.getLicense().isDefined()).thenReturn(Boolean.TRUE); // Null pointer Exception

}

Few lines in my macro code which are throwing null pointer exception

private final ThirdPartyPluginLicenseStorageManager licenseManager;

public Macro(ThirdPartyPluginLicenseStorageManager licenseManager){
        this.licenseManager = licenseManager;
}

PluginLicense pluginLicense = licenseManager.getLicense().get();
if(licenseManager.getLicense().isDefined()) {
	if(pluginLicense.getError().isDefined()) {

}
}

Geoff Williams · Answer

This was helpful but I had to use PowerMock instead of Mockito because the `isDefined` method is final :( I ended up making my own Mock version of PluginLicenseManager with a method like this: @Override public Option getLicense() { Option option = PowerMockito.mock(Option.class); PluginLicense pluginLicense = PowerMockito.mock(PluginLicense.class); Option optionError = PowerMockito.mock(Option.class); PowerMockito.doReturn(error).when(optionError).isDefined(); PowerMockito.doReturn(optionError).when(pluginLicense).getError(); PowerMockito.doReturn(licensed).when(option).isDefined(); PowerMockito.doReturn(pluginLicense).when(option).get(); return option; } error and license being simple booleans defined as part of the class. Also had to make sure my test runner was annotated: @RunWith(PowerMockRunner.class) @PrepareForTest(Option.class) Still get some strange warnings from the depths of PowerMock but it works... WARNING: Illegal reflective access by org.powermock.reflect.internal.WhiteboxImpl (file:/home/geoff/.m2/repository/org/powermock/powermock-reflect/2.0.2/powermock-reflect-2.0.2.jar) to method java.lang.Object.clone() WARNING: Please consider reporting this to the maintainers of org.powermock.reflect.internal.WhiteboxImpl WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations WARNING: All illegal access operations will be denied in a future release HTH

Panos · Answer

Generally the idea is like... when(mockedObject.method()).thenReturn(something) right? In your occassion, licenseManager.getLicense() returns an Option<PluginLicense> so the mock should be:

when(licenseManager.getLicense()).thenReturn(Option.option(pluginLicense));

This is untested though

In mockito you dont do setters. Lets say you have an interface method that with parameter string X returns object T and another method that with object T, returns string X.

the you would

Mockito.when(myInterface.myMethod(anyString())).thenReturn(T); //Notice the anyString() in this case i dont care what the param is.

the second case would be

Mockito.when(myInterface.myOtherMethod(T)).thenReturn(X);

To mock correctly i suggest you a) read documentation ofc and b) have the documentation of the method signatures on hand.

Neeraj Bodhe · Answer

i am new to mockito Can you just give me an example of how to mock this statement as there is no setter method like licenseManager.setLicense() to it.
How to mock this?