How to write a matcher that is not equal to something

Solution 1:

With Mockito framework, you can use AdditionalMatchers

ClassA classA = Mockito.mock(ClassA.class);
Mockito.when(classA.getString(Matchers.eq("a"))).thenReturn("something"); 
Mockito.when(classA.getString(AdditionalMatchers.not(Matchers.eq("a")))).thenReturn("something else");

Hope it helps.

Solution 2:

Use argThat with Hamcrest:

when(classA.getString(argThat(CoreMatchers.not(CoreMatchers.equalTo("a")))...

You might also be able to do this via ordering. If you put one when(anyString) and when(eq("a")) in the correct order, Mockito should test them in order and do the "a" logic when appropriate and then "anyString" logic otherwise.

Solution 3:

In mockito the last stubbing is the most important. This means that you can simply use the standard matchers for your needs:

// "Default" return values.
when(classA.getString(ArgumentMatchers.anyString())).thenReturn(somethingelse);
// Specific return value for "a"
when(classA.getString(ArgumentMatchers.eq("a"))).thenReturn(something);

Note that you have to use ArgumentMatchers for both since you're mixing them.

Solution 4:

I actually took this approach after carefully looking at the suggested answers:

doAnswer(new Answer<String>() {
  public String answer(InvocationOnMock invocation) throws Throwable {
    String originalParam = (String) invocation.getArguments()[0];
    return StringUtils.equalsIgnoreCase(originalParam, "a") ? "Something" : "Something Else";
  }
}).when(classA).getString(anyString());

This allows me to handle more than just two cases by adjusting the return base on the params.