Presented at Velocity Santa Clara 2016, June 22 Relevant links: https://github.com/sstephenson/bats https://github.com/concourse/git-resource/tree/master/test https://github.com/rbenv/ruby-build/tree/master/test

1. @cjcjameson1
Unit and Integration Testing
C.J. Jameson
Better Bash

2. @cjcjameson
I work at Pivotal, I’m a Toolsmith, I tweet some
2

3. @cjcjameson3
Customer = Engineer
Reliability & predictable outcomes
Good bug reports
Eager to make tradeoffs

4. @cjcjameson4
Tradeoffs?
Customization vs. Reuse
User experience vs. Exposing internals
YAGNI

5. @cjcjameson
How good does this need to be?
The tradeoff with your Bash scripts
5
effort
time
¯_(ツ)_/¯
...sorry dude

6. @cjcjameson6
Here’s my shiny tool…?

7. @cjcjameson
cover this square with an image (540 x 480 pixels)
7
STOP
When would
anyone write a
test themselves?

8. @cjcjameson
cover this square with an image (540 x 480 pixels)
8
STOP
When would
anyone write a
test themselves?

9. @cjcjameson
cover this square with an image (540 x 480 pixels)
9
STOP
When would
anyone run
the tests?

10. @cjcjameson10
When would anyone run the tests?
STOP

11. @cjcjameson11
When would anyone run the tests?
P
https://github.com/koalaman/shellcheck

12. @cjcjameson12
1
https://en.wikipedia.org/wiki/Unit_testing
In general, unit tests...1
Find problems early Make change easy
Drive modular designAre documentationMake integration easy

13. @cjcjameson13
You’re writing an installer file
Be documentation
Make integration easy
(esp. across distros)
So your unit tests should help:

14. @cjcjameson14
You’re touching this code for the first and only time
Drive modular designMake change easy
So your unit tests should help:
Be documentation

15. @cjcjameson15
You’re treating the filesystem as a first-class object
Drive modular designFind problems early
So your unit tests should help:

16. @cjcjameson16
You’re writing a shared `common.bash` library
Be documentationMake integration easy
So your unit tests should help:

17. @cjcjameson17
You’re crafting a CLI user experience
Make change easyFind problems early
So your unit tests should help:

18. @cjcjameson18
Example: ruby-build

19. @cjcjameson19
Example: Concourse’s `git-resource`
https://ci.concourse.ci/pipelines/resources/jobs/git-resource

20. @cjcjameson20
Example: “Check the executable bit”

21. @cjcjameson21
Example: “Check the executable bit”

22. @cjcjameson22
Example: “Check the executable bit” - integration

23. @cjcjameson23
Inside the BATS `run` command
https://github.com/sstephenson/bats
- Exit codes are swallowed
- `stdout` and `stderr` are swallowed
- Start by `source`ing in the file under test … so the file runs

24. @cjcjameson24
Thanks!