Sean Carolan, Solutions Architect at Chef Sean delivered this presentation at the Texas DevOps Dallas Meetup on Aug. 26, 2015.

1. Zero to Test Driven Infrastructure
Sean Carolan – Solutions Architect, Chef

2. History of Software Testing
< 1956 Debugging: You found a bug in the code and fixed it.
1957–1978 Demonstration: Does the code run? Does it solve the problem?
1979–1982 Destruction: Kill all the bugs.
1983–1987 Evaluation: SDLC – Each stage has testing methods.
1988–2000 Prevention: Catch bugs and issues *before* they cost $$$(1)
2001-2009 Automation: Automate as much of your testing as possible.
2010–Today Velocity: Test fast and deploy often.
1) Gelperin, D. & Hetzel, B., (1988). The Growth of Software Testing

3. Why test?
• The closer a defect is discovered to its
introduction, the cheaper and easier it is to
fix.
• It is better to find a security violation before
the configuration code touches a production
system, instead of three months later during
a security audit.
• Rigorous testing allows you to deploy
infrastructure changes with confidence. The
more often you deploy code, the more
routine it becomes.

4. Automation is Essential
• Automate the setup, provisioning and deployment of an Apache webserver
• Infrastructure setup steps are defined as code, using the Chef DSL
• Tests are conducted during each stage of the continuous delivery pipeline

5. Three Types of Testing
Signal in: Did I send a properly
formed piece of code to the
interpreter?
Signal processing: Was my well-
formed signal properly interpreted?
Signal out: Did my well-formed
code, correctly interpreted, actually
achieve the thing I set out to do?
The Breakfast Taco API

6. What are the ingredients for success?
Chef workstation.
Can be your laptop
or a VM.
Somewhere to spin
up VMs/containers.
Source Code
Repository
CI system for
automated testing

7. Tools of the Trade
What’s in the Kitchen?

8. Rubocop
Because Ruby
• Identify potential Ruby errors
• Unclosed strings, etc.
• Identify style/convention that helps write better code
• Single quotes vs. double quotes
• This is useful for new Chefs, and helps make the code more readable
• Exclude rules that do not apply
• Not everyone is the same – some tests won’t work for your organization or for Chef code
• Run against static code, so tests are very fast (<1 second to run)

9. Food Critic
Test Your “Chef Style”
• Flag problems that might cause your Chef cookbooks to fail
on converge
FC010: Invalid search syntax
• Identify style/convention that has been adopted by the Chef
community
FC004: Use a service resource to start and stop
services
• Create custom rules for your own organization’s
compliance/standards
COMP001: Do not allow recipes to mount disk volumes
• Run against static code, so tests are very fast (<5 seconds to
run)

10. ChefSpec
Simulate Chef
• Did I send a properly formed piece of code to Chef?
• Especially important if there is mutability in your code
• This can cover things like feature flags, or behavior that changes on a
per-OS basis
• "If on Debian-based Linux I need to install package apache2, but on EL
variants I need to install package httpd.”
• Tests are very fast to run
• Even with simple code, it is useful for new Chefs to find simple errors
quickly
• Useful for regression testing – to make sure new changes
don’t break stuff that worked before.

11. Test Kitchen
Let’s do this (almost) for real
• “Signal Out” testing for Chef code
• Just because I said something and it was interpreted correctly, doesn't mean that
what I said is what I meant.
• Executes your Chef code on a real node. These nodes should be
disposable (local virtualization, cloud instances, etc.)
• Use any number of “signal out” testing products to ensure expected
results
• BATS
• ServerSpec
• Pester
• Can pull in other cookbook dependencies as well, and execute against
a machine that looks the same as your standard image

12. Six hours? Really?
• Hour 1: Visit www.learnchef.com and learn the Chef DSL basics
• Hour 2: Install ChefDK, Vagrant, Virtualbox and the kitchen-vagrant driver
• Hour 3: Write a few ChefSpec and ServerSpec tests for Apache
• Hour 4: Write Chef code so your VM passes the tests (Install, config apache)
• Hour 5: Debug, troubleshoot, fix any errors.
• Hour 6: Sit back, enjoy a Texian Martini and reflect on how awesome you are

13. Pre-built Apache cookbook
• Download a pre-built sample Apache
cookbook to use for testing.
• This is the same cookbook we write in
Chef Fundamentals training.
• Some sample unit and integration tests
are included to get you started.
http://bit.ly/1Iauoft

14. Questions?