Add CLI integration tests

[alexshtin]

Not all CLI commands are covered with unit tests and some sort of integration tests need to be added.

[mfateev]

This might be useful: https://medium.com/swlh/unit-testing-cli-programs-in-go-6275c85af2e7

[rylandg]

Funny enough, I recently released a tool which could solve this problem.

https://github.com/rylandg/shrun

Tests are written as bash in YAML and each one runs in it's own docker container.

---
- test: Simple passing case
  foreach:
    - PY_VERSION: python2
  steps:
    -   in: echo "Hello guys {PY_VERSION}"
        out: |-
          Hello guys {PY_VERSION}
- test: Exit code failure (bad-path)
  steps:
    -   in: Hello world
        err: |-
          bash: line 1: Hello: command not found
        exit: 127
- test: Test help (good-path)
  steps:
    -   in: testshrun help
        out: |-
          You will receive no help with testshrun
- test: Test run (good-path)
  steps:
    -   in: testshrun run
        out: |-
          Running sucks
- test: Test no command (bad-path)
  steps:
    -   in: testshrun
        err: |-
          Please provide a command to testshrun
        exit: 1
- test: Test unknown command (bad-path)
  steps:
    -   in: testshrun madeup
        err: |-
          madeup is not a recognized testshrun command
        exit: 1

Right now it's mostly tailored for Node CLI but it works out of the box with any CLI. It's just a matter of building the image/mounting a volume with the binary and linking it. It's based on a tool I wrote at my last company for unit/e2e testing our CLI, and was running in production for 2 years or so.

[leowmjw]

Maybe can use testscript, used in go internal tests --> https://pkg.go.dev/github.com/rogpeppe/[email protected]/testscript#pkg-overview