UPDATE: I created a gem to cover the functionality of this post. Visit its homepage here.
I was working on my application and I wanted to write some RSpec tests for some controllers having before_filter for some actions.
I didn’t want to explicitly test the behaviour of the filter since it was already tested in another context. I only wanted to test that it is being executed.
Let’s assume that this is our controller:
class FooController < ApplicationController
before_filter :first_filter
before_filter :second_filter, :only => [:edit, :update]
def index
# some code
end
def edit
#some code
end
def update
# some code
end
protected
def first_filter
# do something
end
def second_filter
# do something
end
end
So, we can write the following custom matcher (I placed it under spec/support/matchers/filters.rb):
RSpec::Matchers.define :execute_before_filter do |filter_name, options|
match do |controller|
controller.stubs(filter_name).raises(StandardError.new("Filter executed: #{filter_name}"))
if options[:stub_filters]
options[:stub_filters].each do |filter|
controller.stubs(filter).returns(true)
end
end
result = begin
send(options[:via], options[:on], options[:with])
false
rescue StandardError => e
e.message == "Filter executed: #{filter_name}"
rescue
false
end
result
end
failure_message do |actual|
filter = expected[0]
options = expected[1]
action = options[:on]
with = options[:via]
params = options[:with]
message = "expected #{actual.class} to execute filter #{filter}"
message << " before action #{action}"
message << " [requested via #{with} with params '#{params}']."
end
failure_message_when_negated do |actual|
filter = expected[0]
options = expected[1]
action = options[:on]
with = options[:via]
params = options[:with]
message = "expected #{actual.class} not to execute filter #{filter}"
message << " before action #{action}"
message << " [requested via #{with} with params '#{params}']"
end
end
and then in our controller’s spec we test the filter execution with the following code:
require 'rails_helper'
RSpec.describe FooController, :type => :controller do
it { should execute_before_filter :first_filter, :on => :index, :via => :get }
it { should execute_before_filter :first_filter, :on => :edit, :via => :get, :with => { :id => '1' } }
it { should execute_before_filter :second_filter,
:on => :edit,
:via => :get,
:with => { :id => '1' },
:stub_filters => [:first_filter] }
it { should execute_before_filter :first_filter, :on => :update, :via => :put, :with => { :id => '1' } }
it { should execute_before_filter :second_filter,
:on => :update,
:via => :put,
:with => { :id => :'1' },
:stub_filters => [:first_filter] }
end
We use the :ignore_filters to stub possible prepended filters so that in case they brake due to missing stubbings etc, they don’t mess with our test.
If we comment the before_filter declarations in the FooController => tadaaaaa:
(