Updated API tests to verify they are instrumented.

spec/spec_helper.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 require 'factory_bot'
+require 'rack'
+require 'rack/test'
 
 # Configure code coverage reporting.
 if ENV.fetch('COVERAGE', false)
@@ -14,9 +16,15 @@
   end
 end
 
+# We need to build a Rack app for testing. This ensures that we're including the
+# appropriate middleware and that the app is configured correctly.
+ENV['RACK_ENV'] = 'test'
+RSPEC_APP = Rack::Builder.parse_file('config.ru')
+
 RSpec.configure do |config|
   config.include FactoryBot::Syntax::Methods
 end
 
-# Include factories.
+# Include shared examples and factories.
+require_relative 'support/examples'
 require_relative 'support/factories'

spec/support/examples.rb

@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+require_relative 'examples/instrumented'

spec/support/examples/instrumented.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require 'statsd-instrument'
+
+# Verify endpoint instrumentation.
+RSpec.shared_examples 'instrumented' do |method, path, stat|
+  include StatsD::Instrument::Matchers
+
+  it 'increments the endpoint counter' do
+    expect { send(method, path, defined?(params) ? params : {}) }.to \
+      trigger_statsd_increment("endpoint.#{stat}.requests")
+  end
+
+  it 'measures the endpoint duration' do
+    expect { send(method, path) }.to \
+      trigger_statsd_measure("endpoint.#{stat}.duration")
+  end
+end

spec/unit/document_transfer/api/health_spec.rb

@@ -1,19 +1,18 @@
 # frozen_string_literal: true
 
-require 'rack/test'
-
 require_relative '../../../../lib/api/api'
 require_relative '../../../../lib/api/health'
 
 describe DocumentTransfer::API::Health do
   include Rack::Test::Methods
-  include StatsD::Instrument::Matchers
 
   def app
-    DocumentTransfer::API::API
+    RSPEC_APP
   end
 
   describe 'GET /health' do
+    include_examples 'instrumented', :get, '/health', :health
+
     it 'returns 200' do
       get '/health'
       expect(last_response).to be_ok
@@ -23,9 +22,5 @@ def app
       get '/health'
       expect(last_response.body).to eq({ status: 'ok' }.to_json)
     end
-
-    it 'increments the health check counter' do
-      expect { get '/health' }.to trigger_statsd_increment('health_check')
-    end
   end
 end

spec/unit/document_transfer/api/transfer_spec.rb

@@ -1,16 +1,13 @@
 # frozen_string_literal: true
 
-require 'rack/test'
-
 require_relative '../../../../lib/api/api'
 require_relative '../../../../lib/api/transfer'
 
 describe DocumentTransfer::API::Transfer do
   include Rack::Test::Methods
-  include StatsD::Instrument::Matchers
 
   def app
-    DocumentTransfer::API::API
+    RSPEC_APP
   end
 
   describe 'POST /transfer' do
@@ -35,6 +32,8 @@ def app
       allow(destination).to receive(:transfer).and_return({ path: 'rspec-folder/rspec.pdf' })
     end
 
+    include_examples 'instrumented', :post, '/transfer', :transfer
+
     it 'succeeds' do
       post '/transfer', params