title: RSpec test ArgumentError on method with parameters
body: <p>I'm having problems getting this simple test to pass on RSpec 2.8.</p>
  
  <p>I want to write a simple test for the absence of parameters on a method that requires them (i.e. ArgumentError: wrong number of arguments ('x' for 'y')). </p>
  
  <p>My test is testing a Gem module method like so:</p>
  
  <pre><code>describe "#ip_lookup" do
    it "should raise an ArgumentError error if no parameters passed" do
      expect(@geolocater.ip_lookup).to raise_error(ArgumentError)
    end
  end
  </code></pre>
  
  <p>My gem module code looks like this:</p>
  
  <pre><code>module Geolocater
    def ip_lookup(ip_address)
     return ip_address
    end
  end
  </code></pre>
  
  <p>My spec runs with this output.</p>
  
  <pre><code>Failure/Error: expect(@geolocater.ip_lookup).to raise_error(ArgumentError)
       ArgumentError:
         wrong number of arguments (0 for 1)
       # ./lib/geolocater.rb:4:in `ip_lookup'
       # ./spec/geolocater_spec.rb:28:in `block (3 levels) in &lt;top (required)&gt;'
  </code></pre>
  
  <p>What am I missing here?</p>