ArgumentCaptor A single capture() call captures all vararg elements.

[ChristianSchwarz]

A single ArgumentCaptor.capture() call captures all vararg elements.

mock.varargs("1","2","3");

// captures "1","2","3"
verify(mock).varargs(c.capture()); 

// fails with arguments are different
verify(mock).varargs(c.capture(),
                               c.capture()); 


// captures "1","2","3"
verify(mock).varargs(c.capture(),
                               c.capture(),
                               c.capture()); 

Expected: One capture() call should only capture one vararg argument
Actual: A single ArgumentCaptor.capture() call captures all vararg elements.

[mockitoguy]

Respectful -1. The current actual behavior is more intuitive and looks better in code IMHO.

[bric3]

I agree with @szczepiq, the behaviour makes sense today, that's what I would expect from capture

However I think ArgumentCaptor could benefit from a more explicit API, for hardened tests on vararg. I think it should happen in 2.1.

I'm not sure we will change the behavior or introduce a new API, we will see.

[ChristianSchwarz]

The problem of "a single captor captures all varags" is that you can not ensure that only one argument is passed. Here an example:

mock.vararg("1","2"); 
verify(mock).vararg(captor.capture()); 
//^ should fail cause we want to verify that only one 
//  argument was passed and we want capture it

[mockitoguy]

I don't get the example. I can add assertions on captured values, can I not?

[ChristianSchwarz]

I can add assertions on captured values

Sure, but you can't use the capturing matcher to verify the number of arguments passed to the varargs method like e.g. isNotNull() does.

In the following scenario you can't ensure that the method was always called with exactly 2 arguments:

mock.vararg("1","2","3"); 
mock.vararg("4","5"); 
mock.vararg("6"); 
verify(mock, times(3)).vararg(captor.capture()); 

Maybe this works, haven't tested:

mock.vararg("1","2","3"); 
mock.vararg("4","5"); 
mock.vararg("6"); 
verify(mock, times(3)).vararg(or(anyString(),captor.capture()),
                              or(anyString(),captor.capture()))); 

[mockitoguy]

Hmmm, I take your point that this case is not possible to test ATM. Is it a real use case from one of your tests? It seems like an ultra corner case.

[big-andy-coates]

With #2835 this now works:

ArgumentCaptor<String[]> captor = ArgumentCaptor.forClass(String[].class);
mock.vararg("1","2","3"); 
mock.vararg("4","5"); 
mock.vararg("6"); 
verify(mock, times(3)).vararg(captor.capture()); 

// captor.getAllValues() will return List.of(new String[]{"1","2","3"}, new String[]{"4","5"}, new String[]{"6"})

It is also possible to verify only a single value was passed:

ArgumentCaptor<String> captor = ArgumentCaptor.forClass(String.class);
mock.vararg("1","2","3"); 
mock.vararg("4","5"); 
mock.vararg("6"); 
verify(mock, times(1)).vararg(captor.capture());  // <-- only last call matches.