Effectively Testing Services on Rails - Railsconf 2014
76
Effectively Testing Services Neal Kemp
description
Testing services with Ruby on Rails for Railsconf 2014. Test SOA or external services with ease.
Transcript of Effectively Testing Services on Rails - Railsconf 2014
Effectively
Testing
ServicesNeal Kemp
$ whoami
Iowa native
Now: Californian
Software Developer
Independent Consultant
What I Do
Ruby / Rails
Javascript / Angular
HTML, CSS, etc
what, why & howof testing services
NOT Building testable services
NOT Test-driven development
(necessarily)
… and because I don’t want @dhh to rage
what
What is a service?
Internal “SOA”
Any time you make an HTTP
request to an endpoint in
another repository
why
Why are services important?
Build faster
Makes scaling easier
Use them on virtually every application
Increasingly prevalent
Services are critical to
modern Rails
development
Why is testing services
important?You (should) test everything else
Services compose crucial features
You may encounter problems…
Internal API
Sometimes null responses
Inconsistencies
Catastrophe
Okay? But what about external APIs?
{"id": 24}
{"code": "ANA"}
"goals":[
{
"per":"1",
"ta":"CGY",
"et":"14:11",
"st":"Wrist Shot"
},
{
"per":"2",
"ta":"ANA",
"et":"11:12",
"st":"Backhand"
}
]
"goals": {
"per":"1",
"ta":"CGY",
"et":"14:11",
"st":"Wrist Shot"
}
No versioning!
Snapchat Client
Haphazard documentation
What are the requests?
Bizarre obfuscation
github.com/nneal/snapcat
how
What is different about
services?External network requests
You don’t own the code
On an airplane…
Failure is bad!
No network requests
Don’t interact with services from
test environment* **
* Includes “dummy” APIs
** Using pre-recorded
responses is okay
Assuming:
Rails, rspec
Time to stub!
Built-in Stubbing
Typhoeus
Faraday
Excon
Simplify.
gem 'webmock'
ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../../config/environment', __FILE__)
require 'rspec/autorun'
require 'rspec/rails’
Dir[Rails.root.join("spec/support/**/*.rb")].each { |f| require f }
ActiveRecord::Migration.check_pending! if defined?(ActiveRecord::Migration)
RSpec.configure do |config|
config.infer_base_class_for_anonymous_controllers = false
config.order = 'random’
end
WebMock.disable_net_connect!
spec/spec_helper.rb
module FacebookWrapper
def self.user_id(username)
user_data(username)['id']
end
def self.user_data(username)
JSON.parse(
open("https://graph.facebook.com/#{username}").read
)
end
end
lib/facebook_wrapper.rb
require 'facebook_wrapper'
config/intializers/facebook_wrapper.rb
require 'spec_helper'
describe FacebookWrapper, '.user_link' do
it 'retrieves user link' do
stub_request(:get, 'https://graph.facebook.com/arjun').
to_return(
status: 200,
headers: {},
body: '{
"id": "7901103","first_name": "Arjun",
"locale": "en_US","username": "Arjun"
}'
)
user_id = FacebookWrapper.user_id('arjun')
expect(user_id).to eq '7901103'
end
end
spec/lib/facebook_wrapper_spec.rb
require 'spec_helper'
describe FacebookWrapper, '.user_link' do
it 'retrieves user link' do
stub_request(:get, 'https://graph.facebook.com/arjun').
to_return(
status: 200,
headers: {},
body: '{
"id": "7901103","first_name": "Arjun",
"locale": "en_US","username": "Arjun"
}'
)
user_id = FacebookWrapper.user_id('arjun')
expect(user_id).to eq '7901103'
end
end
spec/lib/facebook_wrapper_spec.rb
require 'spec_helper'
describe FacebookWrapper, '.user_link' do
it 'retrieves user link' do
stub_request(:get, 'https://graph.facebook.com/arjun').
to_return(
status: 200,
headers: {},
body: '{
"id": "7901103","first_name": "Arjun",
"locale": "en_US","username": "Arjun"
}'
)
user_id = FacebookWrapper.user_id('arjun')
expect(user_id).to eq '7901103'
end
end
spec/lib/facebook_wrapper_spec.rb
require 'spec_helper'
describe FacebookWrapper, '.user_link' do
it 'retrieves user link' do
stub_request(:get, 'https://graph.facebook.com/arjun').
to_return(
status: 200,
headers: {},
body: '{
"id": "7901103","first_name": "Arjun",
"locale": "en_US","username": "Arjun"
}'
)
user_id = FacebookWrapper.user_id('arjun')
expect(user_id).to eq '7901103'
end
end
spec/lib/facebook_wrapper_spec.rb
Even Better
No network requests
Fast!
No intermittent failure
Mock-Services
AWS
FB graph mock
OmniAuth
Etc…
gem 'fb_graph-mock'
ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../../config/environment', __FILE__)
require 'rspec/autorun'
require 'rspec/rails’
require 'fb_graph/mock'
Dir[Rails.root.join("spec/support/**/*.rb")].each { |f| require f }
ActiveRecord::Migration.check_pending! if defined?(ActiveRecord::Migration)
RSpec.configure do |config|
config.infer_base_class_for_anonymous_controllers = false
config.order = 'random'
config.include FbGraph::Mock
end
WebMock.disable_net_connect!
spec/spec_helper.rb
describe FacebookWrapper, '.user_link' do
it 'retrieves user link' do
mock_graph :get, 'arjun', 'users/arjun_public' do
user_id = FacebookWrapper.user_id('arjun')
expect(user_id).to eq '7901103'
end
end
end
spec/lib/facebook_wrapper_spec.rb
describe FacebookWrapper, '.user_link' do
it 'retrieves user link' do
mock_graph :get, 'arjun', 'users/arjun_public' do
user_id = FacebookWrapper.user_id('arjun')
expect(user_id).to eq '7901103'
end
end
end
spec/lib/facebook_wrapper_spec.rb
Even Better
Already stubbed for you
Pre-recorded responses (sometimes)
Don’t need to know API endpoints
gem 'sham_rack'
gem 'sinatra'
ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../../config/environment', __FILE__)
require 'rspec/autorun'
require 'rspec/rails’
Dir[Rails.root.join("spec/support/**/*.rb")].each { |f| require f }
ActiveRecord::Migration.check_pending! if defined?(ActiveRecord::Migration)
RSpec.configure do |config|
config.infer_base_class_for_anonymous_controllers = false
config.order = 'random’
end
WebMock.disable_net_connect!
spec/spec_helper.rb
ShamRack.at('graph.facebook.com', 443).sinatra do
get '/:username' do
%Q|{
"id": "7901103",
"name": "Arjun Banker",
"first_name": "Arjun",
"last_name": "Banker",
"link": "http://www.facebook.com/#{params[:username]}",
"location": {
"id": 114952118516947,
"name": "San Francisco, California"
},
"gender": "male"
}|
end
end
spec/support/fake_facebook.rb
ShamRack.at('graph.facebook.com', 443).sinatra do
get '/:username' do
%Q|{
"id": "7901103",
"name": "Arjun Banker",
"first_name": "Arjun",
"last_name": "Banker",
"link": "http://www.facebook.com/#{params[:username]}",
"location": {
"id": 114952118516947,
"name": "San Francisco, California"
},
"gender": "male"
}|
end
end
spec/support/fake_facebook.rb
ShamRack.at('graph.facebook.com', 443).sinatra do
get '/:username' do
%Q|{
"id": "7901103",
"name": "Arjun Banker",
"first_name": "Arjun",
"last_name": "Banker",
"link": "http://www.facebook.com/#{params[:username]}",
"location": {
"id": 114952118516947,
"name": "San Francisco, California"
},
"gender": "male"
}|
end
end
spec/support/fake_facebook.rb
ShamRack.at('graph.facebook.com', 443).sinatra do
get '/:username' do
%Q|{
"id": "7901103",
"name": "Arjun Banker",
"first_name": "Arjun",
"last_name": "Banker",
"link": "http://www.facebook.com/#{params[:username]}",
"location": {
"id": 114952118516947,
"name": "San Francisco, California"
},
"gender": "male"
}|
end
end
spec/support/fake_facebook.rb
describe FacebookWrapper, '.user_link' do
it 'retrieves user link' do
user_id = FacebookWrapper.user_id('arjun')
expect(user_id).to eq '7901103’
end
end
spec/lib/facebook_wrapper_spec.rb
Even Better
Dynamic
Expressive
Readable
gem 'vcr'
ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../../config/environment', __FILE__)
require 'rspec/autorun'
require 'rspec/rails’
Dir[Rails.root.join("spec/support/**/*.rb")].each { |f| require f }
ActiveRecord::Migration.check_pending! if defined?(ActiveRecord::Migration)
RSpec.configure do |config|
config.infer_base_class_for_anonymous_controllers = false
config.order = 'random’
end
WebMock.disable_net_connect!
VCR.configure do |c|
c.cassette_library_dir = 'spec/fixtures/vcr_cassettes'
c.hook_into :webmock
end spec/spec_helper.rb
describe FacebookWrapper, '.user_link' do
it 'retrieves user link' do
VCR.use_cassette('fb_user_arjun') do
user_id = FacebookWrapper.user_id('arjun')
expect(user_id).to eq '7901103'
end
end
end
spec/lib/facebook_wrapper_spec.rb
describe FacebookWrapper, '.user_link' do
it 'retrieves user link' do
VCR.use_cassette('fb_user_arjun') do
user_id = FacebookWrapper.user_id('arjun')
expect(user_id).to eq '7901103'
end
end
end
spec/lib/facebook_wrapper_spec.rb
Even Better
Record API automatically
Replay responses without network
Verify responses
Additional Build Process
Runs outside normal test mode
Rechecks cassettes for diffs
Avoids versioning issues
gem 'puffing-billy'
Puffing-Billy
Built for in-browser requests
Allowed to record and reuse (like VCR)
Be brave, venture out
of ruby
I also like…
Chrome Dev Tools
Postman
HTTPie
Charles
Additional Readingmartinfowler.com/bliki/IntegrationContractTest.html
robots.thoughtbot.com/how-to-stub-external-services-in-tests
joblivious.wordpress.com/2009/02/20/handling-intermittence-how-to-
survive-test-driven-development
railscasts.com/episodes/291-testing-with-vcr
Bringing it all together
Testing services is crucial
If in doubt, stub it out
Determine the flexibility you want
Record responses to save time
Next Up
Eliminating Inconsistent Test Failures
with Austin Putman
