The document is a presentation on Test-Driven Development (TDD) using Puppet, presented by Garrett Honeycutt at the Cascadia IT Conference in 2014. It covers the importance of testing in Puppet modules, the testing workflow, tools, and methodologies for effective module development, including semantic versioning and integration with CI tools like Travis CI. The presentation also features exercises for testing parameters, file content, and coding best practices for Puppet module development.

1. TDD with Puppet
!
Cascadia IT Conference
2014-03-08
Seattle, WA!
!
Garrett Honeycutt
@learnpuppet
gh@learnpuppet.com
http://learnpuppet.com

2. # whoami

3. Where are we
going?
• Why test?
• What makes a good module
• Tools
• SetupVM
• Hack
• Travis-ci
• More Hacking
3

4. LearnPuppet.com
• Training
• 3 day Intro course
• 2 day advanced course
• Consulting
• Auditing
4

5. Why test?
5
• Confidence to change things

6. Why test?
6
• Confidence to change things
• Know when you break something before deploying it

7. Why test?
7
• Confidence to change things
• Know when you break something before deploying it
• Quickly test a matrix of Puppet and Ruby versions

8. Why test?
8
• Confidence to change things
• Know when you break something before deploying it
• Quickly test a matrix of Puppet and Ruby versions
• Test all OS’s without having to deploy it everywhere

9. Why test?
9
• Confidence to change things
• Know when you break something before deploying it
• Quickly test a matrix of Puppet and Ruby versions
• Test all OS’s without having to deploy it everywhere
• Fast feedback

10. Why test?
10
• Confidence to change things
• Know when you break something before deploying it
• Quickly test a matrix of Puppet and Ruby versions
• Test all OS’s without having to deploy it everywhere
• Prevent regression of old problems
• Fast feedback

11. Why test?
11
• Confidence to change things
• Know when you break something before deploying it
• Quickly test a matrix of Puppet and Ruby versions
• Test all OS’s without having to deploy it everywhere
• Prevent regression of old problems
• Fast feedback
• Even in an agile world, we still have design specs.

12. Why test first?
• Puts a focus on what you want to accomplish.
• Documents the functionality that you care about.
• Makes you think about your design.
• Save time by building the minimum viable product first.
• You can refactor later.
12

13. What to test?
• Each parameter
• Each resource
• Ensure that failure occurs when that’s expected
• Conditional logic
13

14. What is actually
tested?
• Catalog is compiled with inputs such as setting values for
facts and parameters
• We test that things are or are not in the catalog
• Simple :)
14

15. Semver
• Explanation of semantic versioning - semver.org
15

16. 1.0.0
• README explains all parameters
• Passes lint
• Works with at least Ruby 1.8.7, 1.9.3, and 2.0.0
• Validates params
• Tests all params
• Tests all flows in logic
16

17. approach to
writing modules
• Write the README first, explaining all of your parameters and their
valid values and their default values.
• Add all of the parameters to your manifests with default values from
the README.
• Write the tests from the README.
• Write just enough code to get your tests to pass.
• Refactor as necessary.
17

18. 18

21. Prep VM
• http://bit.ly/1fdJtwy
• What interface is detected? (ifconfig -a)
• Configure it for DHCP (/etc/sysconfig/network-scripts/
ifcfg-ethX)
• Restart the network (service network restart)
• Modify /etc/hosts and place your IP in there
• Validate (`ping puppet` should work)
• Restart apache (service httpd restart)
• # gem update -V rspec-core rspec
puppetlabs_spec_helper rspec-puppet
21

22. Testing tools
• Only if you are not using the providedVM
$ sudo gem install -V puppet-lint rspec rspec-puppet
puppetlabs_spec_helper --no-ri --no-rdoc
• https://github.com/puppetlabs/puppet-syntax-vim
• https://github.com/puppetlabs/puppet-syntax-emacs
22

23. RVM
http://www.rvm.io/
!
• Allows you to easily switch between multiple versions of Ruby
23

24. Ruby Versions
• 1.8.7
• 1.9.3
• 2.0.0
• 2.1.0
24

25. rspec-puppet
http://rspec-puppet.com/
Thanks,Tim!
25

26. Puppet Module
Skeleton
• $ git clone https://github.com/ghoneycutt/puppet-
module-skeleton
• $ mkdir -p `puppet config print vardir`/puppet-
module/skeleton/
• $ rsync -avp --exclude .git puppet-module-
skeleton/ `puppet config print vardir`/puppet-
module/skeleton/
26

27. Create a module
• generate motd module
$ puppet module generate forgename-motd
27

28. Components
ghoneycutt-motd
ghoneycutt-motd/.fixtures.yml
ghoneycutt-motd/.gitignore
ghoneycutt-motd/.travis.yml
ghoneycutt-motd/Gemfile
ghoneycutt-motd/LICENSE
ghoneycutt-motd/Modulefile
ghoneycutt-motd/README.md
ghoneycutt-motd/Rakefile
ghoneycutt-motd/manifests
ghoneycutt-motd/manifests/init.pp
ghoneycutt-motd/spec
ghoneycutt-motd/spec/classes
ghoneycutt-motd/spec/classes/init_spec.rb
ghoneycutt-motd/spec/fixtures
ghoneycutt-motd/spec/fixtures/manifests
ghoneycutt-motd/spec/fixtures/manifests/site.pp
ghoneycutt-motd/spec/fixtures/modules
ghoneycutt-motd/spec/spec_helper.rb
28

29. Components
ghoneycutt-motd
ghoneycutt-motd/.fixtures.yml
ghoneycutt-motd/.gitignore
ghoneycutt-motd/.travis.yml
ghoneycutt-motd/Gemfile
ghoneycutt-motd/LICENSE
ghoneycutt-motd/Modulefile
ghoneycutt-motd/README.md
ghoneycutt-motd/Rakefile
ghoneycutt-motd/manifests
ghoneycutt-motd/manifests/init.pp
ghoneycutt-motd/spec
ghoneycutt-motd/spec/classes
ghoneycutt-motd/spec/classes/init_spec.rb
ghoneycutt-motd/spec/fixtures
ghoneycutt-motd/spec/fixtures/manifests
ghoneycutt-motd/spec/fixtures/manifests/site.pp
ghoneycutt-motd/spec/fixtures/modules
ghoneycutt-motd/spec/spec_helper.rb
29

30. .fixtures.yml
• List all of your dependencies from Modulefile
30

31. Gemfile
• Used by Bundler
31

32. .travis.yml
• Configure travis-ci.org
32

33. spec_helper.rb
• Code that is run before your spec tests.
• Configures the spec testing environment.
33

34. Rakefile
• Validate syntax
rake validate
!
• Validate style
rake lint
34

35. Rakefile
• show all tasks
rake -T
35

36. rake spec
• rake spec calls
• rake spec_prep
• rake spec_standalone
• rake spec_clean
36

37. run tests
$ SPEC_OPTS=--format documentation rake
spec_standalone
37

38. first test
it {
should contain_file('motd').with({
'ensure' = 'file',
'path' = '/etc/motd',
'owner' = 'root',
'group' = 'root',
'mode' = '0644',
'content' = nil,
})
}
38

39. run tests
• It fails! Now let’s fill in the code.
39

40. testing params
• Each attribute of the file resource should be configurable
through params.
• Let’s test for values that should should work as well as what
should produce an error.
40

41. testing paramsdescribe 'with path specified' do
context 'as a valid path' do
let(:params) { { :path = '/usr/local/etc/motd' } }
!
it {
should contain_file('motd').with({
'path' = '/usr/local/etc/motd',
})
}
end
!
context 'as an invalid path' do
let(:params) { { :path = 'invalid/path' } }
!
it 'should fail' do
expect {
should contain_class('motd')
}.to raise_error(Puppet::Error)
end
end
41

42. testing file content
describe 'with content parameter specified' do
let(:params) { { :content = Welcome to
puppet.learnpuppet.comnnHave Fun!n } }
!
!
it {
should contain_file('motd').with_content(
%{Welcome to puppet.learnpuppet.com
!
Have Fun!
})
}
end
42

43. reading tests
$ grep -ie describe -e context spec/classes/init_spec.rb
describe 'motd' do
context 'with default values for all parameters' do
describe 'with motd_file parameter specified' do
context 'as a valid path' do
context 'as an invalid path' do
describe 'with motd_content parameter specified' do
43

44. Exercise
Test all params
• All attributes of file resource should be configurable.
• Write tests first.
• Then add code to the module.
44

45. four digit mode
describe 'with motd_mode specified' do
context 'as a valid four digit entry' do
let(:params) { { :mode = '0755' } }
!
it {
should contain_file('motd').with({
'mode' = '0755',
})
}
end
!
context 'as an invalid three digit entry' do
let(:params) { { :mode = '755' } }
!
it 'should fail' do
expect {
should contain_class('motd')
}.to raise_error(Puppet::Error,/^motd::mode must be a four digit
string./)
end
end
end
45

46. for loops
['666','66666','invalid',true].each do |mode|
context as invalid value #{mode} do
let(:params) { { :motd_mode = mode } }
!
it 'should fail' do
expect {
should contain_class('motd')
}.to raise_error(Puppet::Error,/^motd::mode must be a four
digit string./)
end
end
end
46

47. Exercise
Validate mode
• Validate mode with validate_re()
https://github.com/puppetlabs/puppetlabs-stdlib/tree/3.2.0#validate_re
• Test your regex at http://rubular.com/
47

48. resource relationships# package
it {
should contain_package('ntp_package').with({
...
})
}
!
# file
it {
should contain_file('ntp_config').with({
...
'require' = 'Package[ntp]',
})
}
!
# service
it {
should contain_service('ntp_service').with({
...
'subscribe' = 'File[ntp_config]',
})
}
48

49. file content
# check for a specific line
!
it { should contain_file('ntp_conf').with_content(/^tinker panic 0$/) }
49

50. file content
# what if the whole line is optional?
# in this case we test that it is not present
!
it { should_not contain_file('ntp_conf').with_content(/^tinker panic 0$/) }
50

51. Exercise
ntp module
• Use the last few slides to guide you on a module for NTP
• Do the minimum amount of work to get the tests to pass.
• Copy /etc/ntp.conf to your module as a starting place
51

52. specify facts
context 'with default values for parameters on
EL 6' do
let(:facts) do
{ :osfamily = 'RedHat',
:lsbmajdistrelease = '6',
}
end
end
52

53. Exercise
add OS to ntp
• Add support for another OS.This OS should have at least a
different name for the package or service.
53

54. 54
GitHub HowTo

55. Travis-ci.org
• Free!
• Matrix testing
• Integrates with GitHub
• Tests every pull request automatically
• Free!
55

56. .travis.yml---
env:
- PUPPET_VERSION=3.3.2
- PUPPET_VERSION=3.4.2
notifications:
email: false
rvm:
- 1.8.7
- 1.9.3
- 2.0.0
language: ruby
before_script: gem install --no-ri --no-rdoc
bundler
script: 'bundle exec rake validate bundle exec
rake lint SPEC_OPTS=--format documentation
bundle exec rake spec'
gemfile: Gemfile
56

57. 57
Integrate with Travis

58. Test functions
# lib/puppet/parser/functions/yell.rb
module Puppet::Parser::Functions
newfunction(:yell, :type = :rvalue, :doc = -EOS
Takes one argument, a string to be capitalized. Returns the
string in
all caps.
EOS
) do |args|
raise(Puppet::ParseError, yell(): Wrong number of arguments +
given (#{args.size} for 1)) if args.size != 1
args[0].upcase
end
end
58

59. Test functions
# spec/functions/yell_spec.rb
require 'spec_helper'
describe 'yell' do
it 'should run with correct number of arguments (1)' do
should run.with_params('hello world').and_return('HELLO WORLD')
end
!
it 'should fail with no arguments' do
should run.with_params().and_raise_error(Puppet::ParseError)
end
!
it 'should fail with more than one argument (2)' do
should run.with_params('too','many').and_raise_error(Puppet::ParseError)
end
end
59

60. Defines# spec/defines/mkdir_p_spec.rb
require 'spec_helper'
describe 'common::mkdir_p' do
context 'should create new directory' do
let(:title) { '/some/dir/structure' }
!
it {
should contain_exec('mkdir_p-/some/dir/structure').with({
'command' = 'mkdir -p /some/dir/structure',
'unless' = 'test -d /some/dir/structure',
})
}
end
!
context 'should fail with a path that is not absolute' do
let(:title) { 'not/a/valid/absolute/path' }
!
it do
expect {
should contain_exec('mkdir_p-not/a/valid/absolute/path').with({
'command' = 'mkdir -p not/a/valid/absolute/path',
'unless' = 'test -d not/a/valid/absolute/path',
})
}.to raise_error(Puppet::Error)
end
end
end
60

61. Exercise
Defines
• Create a define,‘say’, that takes a param,‘msg’ or if msg is not sent,
use the title and pass that to a notify{} resource.
• Write tests first, then write the define.
• Bonus to create your own function to run on the msg, such as
making it all lower case or l33t sp34k.
61

62. Hashes
• https://github.com/ghoneycutt/puppet-module-vim/blob/master/
spec/classes/init_spec.rb
62

63. Exercise
refactor ntp
• Refactor ntp module to use a hash to specify differences between
OS’s
63

64. TDD with Puppet
!
Cascadia IT Conference
2014-03-08
Seattle, WA!
!
Garrett Honeycutt
@learnpuppet
gh@learnpuppet.com
http://learnpuppet.com