Adds Grape::Endpoint.setup for pre-run endpoint config.

CHANGELOG.md

@@ -4,6 +4,7 @@ Next Release
 #### Features
 
 * [#617](https://github.com/intridea/grape/pull/617): Running tests on Ruby 2.1.1, Rubinius 2.1 and 2.2, Ruby and JRuby HEAD - [@dblock](https://github.com/dblock).
+* [#397](https://github.com/intridea/grape/pull/397): Adds `Grape::Endpoint.before_each` to allow easy helper stubbing - [@mbleigh](https://github.com/mbleigh).
 * Your contribution here.
 
 #### Fixes

README.md

@@ -57,6 +57,7 @@
 - [Writing Tests](#writing-tests)
   - [Writing Tests with Rack](#writing-tests-with-rack)
   - [Writing Tests with Rails](#writing-tests-with-rails)
+  - [Stubbing Helpers](#stubbing-helpers)
 - [Reloading API Changes in Development](#reloading-api-changes-in-development)
   - [Rails 3.x](#rails-3x)
 - [Performance Monitoring](#performance-monitoring)
@@ -1606,6 +1607,31 @@ RSpec.configure do |config|
 end
 ```
 
+### Stubbing Helpers
+
+Because helpers are mixed in based on the context when an endpoint is defined, it can
+be difficult to stub or mock them for testing. The `Grape::Endpoint.before_each` method
+can help by allowing you to define behavior on the endpoint that will run before every
+request.
+
+```ruby
+describe 'an endpoint that needs helpers stubbed' do
+  before do
+    Grape::Endpoint.before_each do |endpoint|
+      endpoint.stub!(:helper_name).and_return('desired_value')
+    end
+  end
+
+  after do
+    Grape::Endpoint.before_each nil
+  end
+
+  it 'should properly stub the helper' do
+    # ...
+  end
+end
+```
+
 ## Reloading API Changes in Development
 
 ### Rails 3.x

lib/grape/endpoint.rb

@@ -8,6 +8,18 @@ class Endpoint
     attr_reader :env, :request, :headers, :params
 
     class << self
+      def before_each(new_setup = false, &block)
+        if new_setup == false
+          if block_given?
+            @before_each = block
+          else
+            return @before_each
+          end
+        else
+          @before_each = new_setup
+        end
+      end
+
       # @api private
       #
       # Create an UnboundMethod that is appropriate for executing an endpoint
@@ -383,6 +395,8 @@ def run(env)
 
       cookies.read(@request)
 
+      self.class.before_each.call(self) if self.class.before_each
+
       run_filters befores
 
       run_filters before_validations

spec/grape/endpoint_spec.rb

@@ -7,6 +7,37 @@ def app
     subject
   end
 
+  describe '.before_each' do
+    after { Grape::Endpoint.before_each(nil) }
+
+    it 'should be settable via block' do
+      block = lambda { |endpoint| "noop" }
+      Grape::Endpoint.before_each(&block)
+      expect(Grape::Endpoint.before_each).to eq(block)
+    end
+
+    it 'should be settable via reference' do
+      block = lambda { |endpoint| "noop" }
+      Grape::Endpoint.before_each block
+      expect(Grape::Endpoint.before_each).to eq(block)
+    end
+
+    it 'should be able to override a helper' do
+      subject.get("/") { current_user }
+      expect { get '/' }.to raise_error(NameError)
+
+      Grape::Endpoint.before_each do |endpoint|
+        endpoint.stub(:current_user).and_return("Bob")
+      end
+
+      get '/'
+      expect(last_response.body).to eq("Bob")
+
+      Grape::Endpoint.before_each(nil)
+      expect { get '/' }.to raise_error(NameError)
+    end
+  end
+
   describe '#initialize' do
     it 'takes a settings stack, options, and a block' do
       p = proc {}

spec/spec_helper.rb

@@ -8,6 +8,7 @@
 require 'bundler'
 Bundler.setup :default, :test
 
+require 'json'
 require 'rack/test'
 require 'base64'
 require 'cookiejar'