Shellkin: Gherkin-style testing for command-line tools and shell scripts

[DannyBen]

Hi all,

I will always remember Cucumber as the tool that made testing fun for me, back in my Rails days.

These days, I mostly develop shell scripts and command-line tools, and I wanted to bring that same joy to testing them.

It also complements the way I work with coding agents: Gherkin scenarios are easy for agents to write, while remaining human-readable enough for me to verify that they test the behavior I actually want.

So I developed Shellkin, a Gherkin-style BDD test framework for command-line tools and shell scripts.

The feature stays readable:

Scenario: Show help
  When I run 'mycli --help'
  Then the output should include 'Usage:'

while the implementation is plain shell:

@When I run '{command}'
  run "$command"

@Then the output should include '{text}'
  [[ "$LAST_STDOUT" == *"$text"* ]]

Shellkin is distributed as a single Bash script, built with Bashly, with no runtime dependencies. It supports core Gherkin features including rules, backgrounds, scenario outlines, tags, data tables, doc strings, and lifecycle hooks.

I am sharing it here as my way of giving back, in the hope that others will find it useful. Feedback is very welcome.

P.S. Would it be appropriate to propose adding Shellkin to the Related Tools page on the Cucumber website?

[mpkorstanje]

P.S. Would it be appropriate to propose adding Shellkin to the Related Tools page on the Cucumber website?

Certainly. Though that section of the website needs a serious dusting off.

[DannyBen]

Thanks. Done.