Why is this an issue?

Mockito provides argument matchers and argument captors for flexibly stubbing or verifying method calls.

Mockito.verify(), Mockito.when(), Stubber.when() and BDDMockito.given() each have overloads with and without argument matchers.

However, if argument matchers or captors are used only on some of the parameters, all the parameters need to have matchers as well, otherwise an InvalidUseOfMatchersException will be thrown.

This rule consequently raises an issue every time matchers are not used on all the parameters of a stubbed/verified method.

How to fix it

Code examples

Noncompliant code example

@Test
public void myTest() {
    // Setting up mock responses
    given(foo.bar(anyInt(), i1, i2)).willReturn(null); // Noncompliant, no matchers for "i1" and "i2"
    when(foo.baz(eq(val1), val2)).thenReturn("hi"); // Noncompliant, no matcher for "val2"

    // Simulating exceptions
    doThrow(new RuntimeException()).when(foo).quux(intThat(x -> x >= 42), -1); // Noncompliant, no matcher for "-1"

    // Verifying method invocations
    verify(foo).bar(i1, anyInt(), i2); // Noncompliant, no matchers for "i1" and "i2"

    // Capturing arguments for verification
    ArgumentCaptor<Integer> captor = ArgumentCaptor.forClass(Integer.class);
    verify(foo).bar(captor.capture(), i1, any()); // Noncompliant, no matchers for "i1"
}

Compliant solution

@Test
public void myTest() {
    // Setting up mock responses
    given(foo.bar(anyInt(), eq(i1), eq(i2))).willReturn(null); // Compliant, all arguments have matchers
    when(foo.baz(val1, val2)).thenReturn("hi"); // Compliant, no argument has matchers

    // Simulating exceptions
    doThrow(new RuntimeException()).when(foo).quux(intThat(x -> x >= 42), eq(-1)); // Compliant, all arguments have matchers

    // Verifying method invocations
    verify(foo).bar(eq(i1), anyInt(), eq(i2)); // Compliant, all arguments have matchers

    // Capturing arguments for verification
    ArgumentCaptor<Integer> captor = ArgumentCaptor.forClass(Integer.class);
    verify(foo).bar(captor.capture(), any(), any()); // Compliant, all arguments have matchers
}

Resources