title: rspec match_array for empty array fails?
body: <p>I can't use the <code>match_array</code> to match agains an empty array in one of my tests. I have the following message:</p>
  
  <pre><code>Failure/Error: expect(subject.custom_text_locations).to be match_array([])
  
     expected #&lt;RSpec::Matchers::BuiltIn::MatchArray:105810100&gt; =&gt; #&lt;RSpec::Matchers::BuiltIn::MatchArray:0xc9d1168 @expected=[]&gt;
          got #&lt;Array:105810180&gt; =&gt; []
  </code></pre>
  
  <p>Here is my test:</p>
  
  <pre><code>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 
  </code></pre>
  
  <p>If I change the <code>match_array([])</code> by <code>be_empty</code>, my code works. Also, as pointed by @PeterAlfvin, change <code>custom_text_locations</code> initialization on the subject to <code>[]</code> seems to work.</p>
  
  <p>This is my method:</p>
  
  <pre><code>def custom_text_locations
    self[:custom_text_locations] || []
  end
  </code></pre>
  
  <p>Question: What is wrong with my test?</p>