'matching List in any order when mocking method behavior with Mockito

I have a test using Mockito that has a very strange behavior : it works in debug but fails when running normally. After some investigation, I realized it's because I am mocking methods behavior, passing a list of elements to match. But for some reason, order in the list is not always the same so it doesn't match and what I expect my mock to return is not returned, because the 2 lists are not "equals" 

 when(mockStatusCalculatorService.calculateStatus(Arrays.asList(IN_PROGRESS, ABANDONNED,EXPIRED))).thenReturn(ConsolidatedStatus.EXPIRED);

In my case, order of elements to match doesn't matter. So how can I specify this when configuring my mock ?

javaunit-testingmockito


Solution 1:[1]

If you have Mockito prior to version 2.1.0:

Use the Hamcrest containsInAnyOrder matcher.

when(myMock.myMethod(argThat(containsInAnyOrder(IN_PROGRESS, ABANDONED, EXPIRED))))
    .thenReturn(myValue);

Thank you to @kolobok for pointing out that as from Mockito 2.1.0 (which came out after I wrote this answer), this no longer works.

So for version 2.1.0 and above:

add a dependency on Hamcrest, and use the MockitoHamcrest.argThat instead of Mockito.argThat

More detail on the breaking change with Mockito 2.1.0 is at https://www.javadoc.io/doc/org.mockito/mockito-core/2.1.0/org/mockito/ArgumentMatcher.html

Solution 2:[2]

Adding an answer for newer versions of Mockito and Java 8

when(
   mock.method(argThat(t -> t.containsAll(Arrays.asList(IN_PROGRESS, ABANDONED, EXPIRED))))
).thenReturn(myValue);

Solution 3:[3]

it's actually quite simple. we need a custom matcher :

import org.apache.commons.collections.CollectionUtils;
import org.mockito.ArgumentMatcher;
import java.util.List;
import static org.mockito.Matchers.argThat;

public class InAnyOrderListMatcher extends ArgumentMatcher<List> {

private final List expected;

public InAnyOrderListMatcher(List expected){
    this.expected=expected;
}

@Override
public boolean matches(Object actual) {

    if(actual instanceof List){

        List actualList=(List)actual;

        return CollectionUtils.isEqualCollection(expected,actualList);

    }

    return false;
}

public static List inAnyOrderListMatcherEq(List expected) {
    return argThat(new InAnyOrderListMatcher(expected));
}

}

And then call it in the test :

when(mockStatusCalculatorService.calculateStatus( inAnyOrderListMatcherEq(Arrays.asList(IN_PROGRESS, ABANDONNED,EXPIRED)))).thenReturn(ConsolidatedStatus.EXPIRED);

Solution 4:[4]

If order does not matter, change your StatusCalculator service to accept a Set instead of a Collection. Then equals will return true regardless of order.

Better to fix your API than hack around it in your unit tests.

Sources

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Source: Stack Overflow

Solution Source
Solution 1
Solution 2 shinjw
Solution 3 Vincent F
Solution 4

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