title: Rspec: using OR in expect .to eq statement
body: <p>I have an rspec test where I want to ensure that only two values can be passed into my instance variable.  I noticed that <code>should satisfy</code> with a block seems to be the more accepted way to test where two outcomes are acceptable, but i'd like to implement an <code>expect().to eq()</code> as illustrated below:</p>
  
  <pre><code>it "only allows -2 or 2 as values" do
      expect (@note.value).to eq(2 or -2)
    end
  </code></pre>
  
  <p>Is this correct syntax for my desired rspec testing?  I understand the idea behind a <code>should</code> statement, and i'm more concerned with the idea as to why <code>should</code> is preferable (if that's actually the case) to using <code>expect .to eq</code> with compound expectations.</p>
  
  <p>Thank you.</p>