Mockito: How do I verify that the array passed to my method contains the right object?

Question

I’m using Mockito 1.9.5. I want to verify that my method (which takes an array as a param) was called in which the array contains exactly one specific object. I’m having trouble figuring out how to do this. I have

Mockito.doReturn(new SaveResult[]{}).when(mockConnection).update(org.mockito.Matchers.any(SObject[].class));
…     

Mockito.verify(mockConnection, Mockito.times(1)).update( new Account[]{ acct });

Unsurprisingly, the second line fails because although the argument, “acct” is the same as what is passed, the enclosing array is not. What is the best way to check for this?

Answer 1

Mockito has a builtin matcher, AdditionalMatchaer#aryEq(T[]) for this usecase exactly:

Mockito.verify(mockConnection, Mockito.times(1))
       .update(aryEq(new Account[]{ acct }));

Answer 2

In addition to Mockito's built-in aryEq() matcher, you can use argThat() with one of Hamcrest's array Matchers. The arrayContaining matcher is a good starting point.

Note that in modern versions of Mockito (newer than 2.1.0 in Sept 2016), you'll need to use MockitoHamcrest.argThat; ArgumentMatchers.argThat (exposed via static inheritance as Mockito.argThat) no longer depends on Hamcrest. This avoids a version dependency between Hamcrest and Mockito's core files.

Though MockitoHamcrest was considered for separation/deprecation/deletion in 2019 (see mockito#1817 and mockito#1819) the file still exists without visible deprecation as of v4.3.1 in January 2022. ArgumentMatchers.argThat is still preferable for lambdas and small custom implementations, but to use Hamcrest's extensive built-in matcher library you'll need MockitoHamcrest as an adapter (or you'll need to adapt it yourself via ArgumentMatchers.argThat).