allow stubbing of helper methods

README.md

@@ -1194,6 +1194,37 @@ RSpec.configure do |config|
 end
 ```
 
+### Mocking and Stubbing helper methods
+
+helpers are defined on a helper object which can be stubbed out.
+
+```ruby
+require 'spec_helper'
+
+describe Twitter::API do
+  describe "logged in behaviour" do
+    it "returns an the user's statuses" do
+      user = double(statuses: [1])
+      Twitter::API.helper.stub(:current_user).and_return(user)
+      get "/api/v1/statuses"
+      response.status.should == 200
+      JSON.parse(response.body).should == [1]
+    end
+  end
+
+  describe "logged out behaviour" do
+
+    it "returns an empty array when user's logged out" do
+      Twitter::API.helper.stub(:current_user).and_return(nil)
+      get "/api/v1/statuses"
+      response.status.should == 200
+      JSON.parse(response.body).should == []
+    end
+  end
+end
+````
+
+
 ## Reloading API Changes in Development
 
 ### Rails 3.x

lib/grape.rb

@@ -19,6 +19,7 @@
 I18n.load_path << File.expand_path('../grape/locale/en.yml', __FILE__)
 
 module Grape
+  autoload :HelperObject,        'grape/helper_object'
   autoload :API,                 'grape/api'
   autoload :Endpoint,            'grape/endpoint'
   autoload :Route,               'grape/route'

lib/grape/api.rb

@@ -268,6 +268,12 @@ def helpers(new_mod = nil, &block)
           change!
           mod
         end
+        helper.extend(mod)
+        mod
+      end
+
+      def helper
+        @helper ||= HelperObject.new
       end
 
       # Add an authentication type to the API. Currently
@@ -307,7 +313,8 @@ def mount(mounts)
           endpoints << Grape::Endpoint.new(settings.clone, {
             :method => :any,
             :path => path,
-            :app => app
+            :app => app,
+            :klass => self
           })
         end
       end
@@ -328,6 +335,7 @@ def route(methods, paths = ['/'], route_options = {}, &block)
         endpoint_options = {
           :method => methods,
           :path => paths,
+          :klass => self,
           :route_options => (@namespace_description || {}).deep_merge(@last_description || {}).deep_merge(route_options || {})
         }
         endpoints << Grape::Endpoint.new(settings.clone, endpoint_options, &block)

lib/grape/endpoint.rb

@@ -45,6 +45,7 @@ def initialize(settings, options = {}, &block)
         @block = self.class.generate_api_method(method_name, &block)
       end
       @options = options
+      @klass = options[:klass]
 
       raise Grape::Exceptions::MissingOption.new(:path) unless options.key?(:path)
       options[:path] = Array(options[:path])
@@ -358,12 +359,25 @@ def endpoints
       end
     end
 
+    def helper
+      @klass.helper if @klass
+    end
+
+    def method_missing(method_name, *args, &block)
+      if helper.respond_to?(method_name)
+        helper.set_context(params, request, env)
+        helper.send(method_name, *args, &block)
+      else
+        super
+      end
+    end
+
     def run(env)
       @env = env
       @header = {}
       @request = Grape::Request.new(@env)
 
-      self.extend helpers
+      #self.extend helpers
       cookies.read(@request)
 
       run_filters befores

lib/grape/helper_object.rb

@@ -0,0 +1,20 @@
+module Grape
+  class HelperObject
+
+    def set_context(params, request, env)
+      reset_context
+      @params = params
+      @request = request
+      @env = env
+    end
+
+    def reset_context
+      instance_variables.each do |name|
+        next if name.to_s == "@mock_proxy"
+        instance_variable_set(name, nil)
+      end
+    end
+
+    attr_reader :params, :request, :env
+  end
+end

lib/grape/version.rb

@@ -1,3 +1,3 @@
 module Grape
-  VERSION = '0.4.2'
+  VERSION = '0.4.3'
 end

spec/grape/api_spec.rb

@@ -835,6 +835,26 @@ def secret
       last_response.body.should eql 'always there:only in admin'
     end
 
+    it "allows stubbing helpers" do
+      subject.helpers do
+        def foo
+          'foo'
+        end
+      end
+
+      subject.get "/" do
+        foo
+      end
+
+      get "/"
+      last_response.body.should eql "foo"
+
+      subject.helper.stub!(:foo).and_return("bar")
+
+      get "/"
+      last_response.body.should eql "bar"
+    end
+
     it 'is reopenable' do
       subject.helpers do
         def one