Test Driven Development for Puppet

Puppet Camp London presentation introducing the tools and techniques used for testing Puppet code. Also introduces Test Driven Development, what it is and why it's useful.

Transcript

1. Test Driven Development! for Puppet! Puppet needs software development Gareth Rushgrove
2. Who (Who is this person?)
3. @garethr
4. UK Government Digital Service
8. The problem (This isn’t a rant, but…)
9. Who here is a software developer? Gareth Rushgrove
10. If you’re writing Puppet code you’re a software developer Gareth Rushgrove
11. As a software developer it’s your job to learn software engineering practices Gareth Rushgrove
12. What is Test Driven Development (And why should you care)
13. A common practice in software engineering Gareth Rushgrove
14. Not just testing Gareth Rushgrove
15. Encourages simple designs and inspires confidence Gareth Rushgrove
16. First write an (initially failing) automated test case Gareth Rushgrove
17. Then produce the minimum amount of code to pass that test Gareth Rushgrove
18. And finally refactor the new code to acceptable standards Gareth Rushgrove
19. Test Driven Design Gareth Rushgrove
20. Gareth Rushgrove
21. Unit testing with RSpec and Guard (Not puppet specific)
22. A unit is the smallest testable part of an application Gareth Rushgrove
23. Testing puppet requires a little Ruby knowledge so we’ll use Ruby examples Gareth Rushgrove
24. class Person def say(word) end end Gareth Rushgrove
25. First lets write a test. For this we use the RSpec testing framework Gareth Rushgrove
26. require 'person' ! describe Person, "#say" do it "should say something" do ! end end Gareth Rushgrove
27. require 'person' ! describe Person, "#say" do it "should say something" do bob = Person.new bob.say("hello").should \ eq("hello everyone") end end Gareth Rushgrove
28. Now lets run our test. It should fail Gareth Rushgrove
29. rspec Gareth Rushgrove
30. Failures: 1) Person#say should say something Failure/Error: bob.say("hello").should eq("hello everyone") expected: "hello everyone" got: nil Finished in 0.00171 seconds 1 example, 1 failure Gareth Rushgrove
31. Now lets write the implementation Gareth Rushgrove
32. class Person def say(word) word + " everyone" end end Gareth Rushgrove
33. And run our test again Gareth Rushgrove
34. Person#say should say something ! Finished in 0.00199 seconds 1 example, 0 failures Gareth Rushgrove
35. Why not have tests automatically run whenever you change the code? Gareth Rushgrove
36. That’s what Guard does Gareth Rushgrove
37. guard :rspec, cmd: 'bundle exec rspec' do watch(%r{^spec/.+_spec\.rb$}) watch(%r{^lib/.+\.rb$}) { 'spec' } end Gareth Rushgrove
38. guard Gareth Rushgrove
39. Lets see a quick demo Gareth Rushgrove
40. Why test puppet code at all (Testing declarative languages)
41. Modules increasingly contain logic Gareth Rushgrove
42. Modules increasingly take arguments Gareth Rushgrove
43. Modules increasingly have interfaces with other modules Gareth Rushgrove
44. Modules increasingly used in many operating system and version combinations Gareth Rushgrove
45. Modules increasingly used in many Ruby and Puppet version combinations Gareth Rushgrove
46. Unit testing puppet with rspec-puppet (Finally some puppet code)
47. Unit testing for Puppet
48. A very simple puppet class Gareth Rushgrove
49. class sample { } Gareth Rushgrove
50. First write the test Gareth Rushgrove
51. require 'spec_helper' ! describe "sample" do it { should create_file('/tmp/sample')} end Gareth Rushgrove
52. Then run the test Gareth Rushgrove
53. sample should contain File[/tmp/sample] (FAILED - 1) ! Finished in 0.4584 seconds 1 example, 1 failure Gareth Rushgrove
54. And then write the (puppet) code to make the test pass Gareth Rushgrove
55. class sample { file { "/tmp/sample": ensure => present, } } Gareth Rushgrove
56. sample should contain File[/tmp/sample] ! Finished in 0.3881 seconds 1 example, 0 failures Gareth Rushgrove
57. Lets run the tests automatically whenever you change anything Gareth Rushgrove
58. guard :rspec, cmd: 'bundle exec rspec' do watch(%r{^spec/.+_spec\.rb$}) watch(%r{^manifests/.+\.pp$}) { 'spec' } end Gareth Rushgrove
59. Lets see a quick demo of that too Gareth Rushgrove
60. You can also test hosts, defines, facts, functions, hieradata Gareth Rushgrove
61. Syntax checking, linting, oh my (Creating a build process)
62. puppet-lint Gareth Rushgrove
63. Puppet! style guide
64. Available! as a gem
65. puppet-lint --with-filename /etc/puppet/modules foo/manifests/bar.pp: trailing whitespace found on line 1 apache/manifests/server.pp: variable not enclosed in {} on line 56 Gareth Rushgrove
66. puppet-syntax Gareth Rushgrove
67. Validate Puppet and ERB syntax
68. require 'puppet-syntax/tasks/puppet-syntax' Gareth Rushgrove
69. rake syntax ---> syntax:manifests ---> syntax:templates ---> syntax:hiera:yaml Gareth Rushgrove
70. What is Rake and why do we use it (Still no puppet)
71. Rake is a Ruby! build tool Gareth Rushgrove
72. It’s like Make but in Ruby Gareth Rushgrove
73. It’s very easy to distribute Rake tasks as Ruby gems Gareth Rushgrove
74. rake Gareth Rushgrove
75. rake <command> Gareth Rushgrove
76. rake -T Gareth Rushgrove
77. Lets make a command to run lint, syntax and spec Gareth Rushgrove
78. task :test => [ :syntax, :lint, :spec, ] Gareth Rushgrove
79. rake test Gareth Rushgrove
80. Acceptance testing with beaker (Living on the edge)
81. Acceptance test against real systems Gareth Rushgrove
82. Test what actually happens, not what is meant to happen Gareth Rushgrove
83. Build by Gareth Rushgrove
84. Very new Gareth Rushgrove
85. Test against different operating systems Gareth Rushgrove
86. HOSTS: ubuntu-server-12042-x64: roles: - master platform: ubuntu-server-12.04-amd64 box: ubuntu-server-12042-x64-vbox4210-nocm box_url: http://puppet-vagrant-boxes.puppetlabs.com/u hypervisor: vagrant ! CONFIG: log_level: verbose type: foss Gareth Rushgrove
87. HOSTS: centos-64-x64: roles: - master platform: el-6-x86_64 box : centos-64-x64-vbox4210-nocm box_url : http://puppet-vagrant-boxes.puppetlabs.com/ hypervisor : vagrant ! CONFIG: log_level: verbose type: foss Gareth Rushgrove
88. Supports multiple hypervisors Gareth Rushgrove
89. Vagrant hypervisor
90. VSphere hypervisor
91. Helpers to install puppet and modules Gareth Rushgrove
92. install_puppet Gareth Rushgrove
93. puppet('module', 'install', 'puppetlabs-stdlib') Gareth Rushgrove
94. Test that Puppet runs without errors Gareth Rushgrove
95. context 'default parameters' do it 'should work with no errors' do pp = “class { 'sample': }” ! expect(apply_manifest(pp).exit_code).to_not eq(1) end end Gareth Rushgrove
96. Test runs are idempotent Gareth Rushgrove
97. context 'default parameters' do it 'should work with no errors' do pp = “class { 'sample': }” ! expect(apply_manifest(pp).exit_code).to_not eq(1) expect(apply_manifest(pp).exit_code).to eq(0) end end Gareth Rushgrove
98. Test that the module installs packages, run services, etc. Gareth Rushgrove
99. Gareth Rushgrove
100. describe package('nginx') do it { should be_installed } end ! describe service('nginx') do it { should be_enabled } it { should be_running } end ! describe port(80) do it { should be_listening} end Gareth Rushgrove
101. Other useful tools (and what we’re still missing)
102. Fixtures, matchers
103. Gareth Rushgrove
104. Nice continuous integration
106. Test pull request branches too
107. --- language: ruby bundler_args: --without development before_install: rm Gemfile.lock || true rvm: - 1.8.7 - 1.9.3 - 2.0.0 script: bundle exec rake test env: - PUPPET_VERSION="~> 2.7.0" - PUPPET_VERSION="~> 3.1.0" - PUPPET_VERSION="~> 3.2.0" - PUPPET_VERSION="~> 3.3.0" - PUPPET_VERSION="~> 3.4.0" Gareth Rushgrove
108. Official! ruby support
109. matrix: exclude: - rvm: 2.0.0 env: PUPPET_VERSION="~> 2.7.0" - rvm: 2.0.0 env: PUPPET_VERSION="~> 3.1.0" - rvm: 1.9.3 env: PUPPET_VERSION="~> 2.7.0" Gareth Rushgrove
110. Experimental code coverage support in rspec-puppet master Gareth Rushgrove
111. at_exit { RSpec::Puppet::Coverage.report! } Gareth Rushgrove
112. Total resources: 24 Touched resources: 8 Resource coverage: 33.33% ! Untouched resources: Class[Nginx] File[preferences.d] Anchor[apt::update] Class[Apt::Params] File[sources.list] Exec[Required packages: 'debian-keyring debian-arch Anchor[apt::source::nginx] Class[Apt::Update] File[configure-apt-proxy] Apt::Key[Add key: 7BD9BF62 from Apt::Source nginx] Anchor[apt::key/Add key: 7BD9BF62 from Apt::Source Anchor[apt::key 7BD9BF62 present] File[nginx.list] Gareth Rushgrove
113. A puppet module skeleton with everything working out of the box Gareth Rushgrove
114. puppet module skeleton
115. puppet module generate sample Gareth Rushgrove
116. A pretty complete example (The Docker module)
117. Gareth Rushgrove
118. Gareth Rushgrove Featured on the Forge
119. Gareth Rushgrove 50 pull request and counting
120. Gareth Rushgrove Contributing guidelines
121. Gareth Rushgrove
122. Gareth Rushgrove Currently has 121 tests
123. 6 classes, 2 defines, 413 lines of puppet code, 387 lines of test code Gareth Rushgrove
124. Take away (If all you remember is…)
125. Infrastructure as code Gareth Rushgrove
126. The first test is the hardest Gareth Rushgrove
127. Politely demand tests for contributions Gareth Rushgrove
128. Test the interface not the implementation Gareth Rushgrove
129. Questions? (And thanks for listening)