Constructor Injected Class Instance Variable Loses Mocking doThrow or doReturn Doesn't work

I have a spring boot application and am using MockitoSugar to write tests. Spring boot version: 2.0.5.RELEASE Scala version: 2.11.8 mockito-scala_2.11: 1.2.4

Injecting mock in constructor:

 val headerParamsResolverMock = mock[HeaderParamsResolver]
 val irsArgumentResolver = new IRSArgumentResolver(headerParamsResolverMock)

Test Case:

"resolverArgument" should "invoke resolve method if header parameter is not resolved" in {
val parameter = mock[Parameter]
doReturn(parameter, Nil: _*).when(methodParameterMock).getParameter
doReturn("string", Nil: _*).when(parameter).getName
doReturn(false, Nil: _*).when(headerParamsResolverMock).isResolved
doReturn("string", Nil: _*).when(headerParamsResolverMock).resolve(mock[NativeWebRequest]) // doesn't work


irsArgumentResolver.resolveArgument(methodParameterMock, mock[ModelAndViewContainer], mock[NativeWebRequest],
    mock[WebDataBinderFactory])

Mockito.verify(headerParamsResolverMock).resolve(mock[NativeWebRequest])
}

Class under test

 @Component
 public final class IRSArgumentResolver implements HandlerMethodArgumentResolver {

private HeaderParamsResolver headerParamsResolver;

public IRSArgumentResolver(HeaderParamsResolver headerParamsResolver) {
    this.headerParamsResolver = headerParamsResolver;
 }
@Override
public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest webRequest,
                              WebDataBinderFactory binderFactory) {

    String sample = "";
    if (!headerParamsResolver.isResolved())
        sample = headerParamsResolver.resolve(webRequest);

    System.out.println(sample); // here its null 
    return webRequest.getParameter(parameter.getParameter().getName());
}

}

If I see the debugger, the headerParamsResolver isn’t shown as a mock object like other method parameters show up. Like Mock for Method Paramater OR Mock for ModelAndViewContainer etc. Moreover, only the isResolved class instance variable is set but other mock features like doThrow or doReturn doesn’t work. PFA debugger screen.

Moreover, this test case throws exception:

[bbonanno]

@gursahibsahni There are quite a few things wrong with this, let’s separate them in 2

1. The project you uploaded to GitHub fails because maven resolves the wrong artifacts all around, similar to this bug, I had to manually add mockito-core and bytebuddy to make it run.

        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-core</artifactId>
            <version>2.25.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>net.bytebuddy</groupId>
            <artifactId>byte-buddy</artifactId>
            <version>1.9.7</version>
        </dependency>
        <dependency>
            <groupId>net.bytebuddy</groupId>
            <artifactId>byte-buddy-agent</artifactId>
            <version>1.9.7</version>
        </dependency>

1. The test you wrote has some issues

• The cause of the exception you posted is that you can’t create a mock while you are verifying (line 57), I guess you probably want something like

Mockito.verify(headerParamsResolverMock).resolve(any[NativeWebRequest])

• HeaderParamsResolver is being mocked properly, the fact that it looks like the real thing in the debugger is due to how the inline mocker works
• Line 50 should stub false (I guess this is a typo as in the code above it does that)
• The last stubbing is never going to work as nothing is gonna be equal to a mock you create and dispose, again I guess you want

doReturn("string", Nil: _*).when(headerParamsResolverMock).resolve(any[NativeWebRequest])

• You still use pretty much the Java Mockito everywhere, if you were to use mockito-scala, your test would look more like

  "resolverArgument" should {
    "invoke resolve method if header parameter is not resolved" in {
      val parameter = mock[Parameter]

      doReturn(parameter).when(methodParameterMock).getParameter
      doReturn("string").when(parameter).getName
      doReturn(false).when(headerParamsResolverMock).isResolved
      doReturn("string").when(headerParamsResolverMock).resolve(*)
      
      irsArgumentResolver.resolveArgument(methodParameterMock, mock[ModelAndViewContainer], mock[NativeWebRequest], mock[WebDataBinderFactory])

      verify(headerParamsResolverMock).resolve(*)
    }
  }

[gursahibsahni]

thanks for the instructions