How to test non-zero return codes?

I was surprised to see shellac throw an error when the command exits non-zero. I was expecting exit-code to be part of the normal object returned, because I don’t think its shellac’s business to decide what semantics apply to my exit codes.

To boil it down lets say I have these two tests:

  it(`should exit 1`, async () => {
    await expect(shellac.default`
      $ echo foo >&2; false
    `).rejects.toEqual(expect.objectContaining({ retCode: 1 }))
  })

  it(`should write to stderr`, async () => {
    await expect(shellac.default`
      $ echo foo >&2; false
    `).rejects.toEqual(expect.objectContaining({ stderr: "foo" }))
  })

The first test works fine. Yes I was surprised to see its a rejection, but it’s simple to test the return code. The 2nd test fails though because as far as I can tell there’s no stderr in the rejection object.

Does shellac offer a way to test stderr is handled correctly in this case? Maybe I’ve missed something…?

Other than that it’s been nice to use the library! 👍 💪

(FWIW this is the actual code I’m using shellac for: https://github.com/gaggle/svgs-to-pdf/blob/main/test/svgs-to-pdf.spec.js)

[geelen]

Done. Merged in #5, released in v0.4.1 and documented in the README here: https://github.com/geelen/shellac#non-zero-exit-codes

[gaggle]

I opted for the return-checking only because it’s what I’m used to. I think I felt it was a bit more arrange/act/assert-ish, if that makes sense? But I don’t actually mind and I’ve been considering changing to the inline so, yeah, maybe this is when I do it. I do agree your example reads a bit cleaner, so I’ll at least give it a shot next I’m in the project.