title: Elixir assert_raise doesn't catch exceptions
body: <p>I wrote this test case:</p>
  
  <pre><code>assert_raise ArgumentError, myFn(a,b)
  </code></pre>
  
  <p>but it does not evaluate in the way I'd expect. <code>myFn</code> raises an ArgumentError (<code>do: raise ArgumentError</code>), but it is not caught by <code>assert_raise</code>. </p>
  
  <p>The example in the docs works just fine:</p>
  
  <pre><code>assert_raise ArithmeticError, fn -&gt;
    1 + "test"
  end
  </code></pre>
  
  <p>From the documentation:</p>
  
  <blockquote>
    <p><code>assert_raise(exception, function)</code><br>
    Asserts the <code>exception</code> is raised during <code>function</code> execution. Returns the rescued exception, fails otherwise</p>
  </blockquote>
  
  <p>I'm guessing that in my test case, the arguments are evaluated first. But how should I've written it?</p>