problem with rspec test, undefined method 'post'

I am writing a spec to test the behavior of the mashup_controller when someone sends a query through a URL. I need to simulate the parameters contained in the URL, and i read that the post() method will do that, however when i get an error:

1) MashupController simulates query
     Failure/Error: post :create
     NoMethodError:
       undefined method `post' for
#<RSpec::Core::ExampleGroup::Nested_1:0x980bc50>
     # ./mashup_controller_rspec.rb:9:in `block (2 levels) in <top (required)>'

Finished in 0.20199 seconds 1 example, 1 failure

Failed examples:

rspec ./mashup_controller_rspec.rb:7 # MashupController simulates query

Here is my code:

require 'spec_helper'
require 'mashup_controller.rb'

describe MashupController do
    it "simulates query" do
        post :create    
    end
end

Sorry if I'm not making any sense. I am very new to rails and rspec. Any help would be appreciated. Thanks.