rspec match_array for empty array fails?

Question

I can't use the match_array to match agains an empty array in one of my tests. I have the following message:

Failure/Error: expect(subject.custom_text_locations).to be match_array([])

   expected #<RSpec::Matchers::BuiltIn::MatchArray:105810100> => #<RSpec::Matchers::BuiltIn::MatchArray:0xc9d1168 @expected=[]>
        got #<Array:105810180> => []

Here is my test:

context 'when there is no custom text locations' do
  subject { create(:service, custom_text_locations: nil) }
  it 'returns empty list' do
    expect(subject.custom_text_locations).to match_array([])
  end 
end

If I change the match_array([]) by be_empty, my code works. Also, as pointed by @PeterAlfvin, change custom_text_locations initialization on the subject to [] seems to work.

This is my method:

def custom_text_locations
  self[:custom_text_locations] || []
end

Question: What is wrong with my test?

That's odd. If you replace subject.custom_text_locations with [] does it pass? If you print subject.custom_text_locations.inspect before the expect, what do you get? — Peter Alfvin
– Peter Alfvin, Commented Feb 11, 2014 at 16:59
@PeterAlfvin You got it right, if I replace by [] it works. rspec version 2.14.7. I'm adding the method also, since it seems to be involved the problem. — fotanus
– fotanus, Commented Feb 11, 2014 at 18:06

Peter Alfvin · Accepted Answer · 2014-02-11 18:13:27Z

26

+50

The code you posted is not the code that generated the error you posted.

The error you posted includes the incorrect to be match_array([]) which is very different from the correct to match_array([]) you have in your posted code.

answered Feb 11, 2014 at 18:13

Peter Alfvin

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4 Comments

fotanus Over a year ago

Are you a seer or something? :O

fotanus Over a year ago

I'm unaccepting your answer then I can award you some extra points with a bounty hunter.

Peter Alfvin Over a year ago

Hardly a seer, more like a blind man. ;-) I'd been staring at and missing that difference for longer than I care to admit!

Peter Alfvin Over a year ago

@fotanus Thanks, that's generous. :-)

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