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Use bats for testing bash wrappers

  • Status: accepted
  • Deciders: Compliant Kubernetes Architecture Meeting
  • Date: 2021-06-03

Context and Problem Statement

We write wrapper scripts for simpler and consistent operations. How should we test these scripts?

Decision Drivers

  • We want to use the best tools out there.
  • We want to reduce tools sprawl, i.e., the collective cost (e.g., training) of adding a new tool should outweigh the collective benefit of the new tool.
  • We want to make contributions inviting.

Considered Options

  • Do not test bash scripts. (We write perfect scripts 100% of the time, right? :smile:)
  • Use alias for mocking, diff and test for assertions.
  • Use bats

Decision Outcome

Chosen option: "bats", because the benefit of using a standard and rather light tool outweighs the cost of collective training on the new tool.

Positive Consequences

  • We use a pretty standard tool for testing in the bash universe.
  • We do not risk re-inventing the while by writing our own wrappers around alias, diff and test.

Negative Consequences

  • We need to learn another tool, fortunately, it seems pretty light.

Other Considerations

Be very mindful about not overusing bash. Generally bash should only be used for things that you would do in the terminal, but got tired of copy-pasting, like:

  • Running commands
  • Copying files
  • Setting environment variables
  • Minor path translations

For more advanced functionality prefer upstreaming into Ansible roles/libraries, Helm Charts, upstream source code, etc.