Same defect as buildkite/test-collector-python#132, which was merged yesterday. I went looking for it here after fixing it there.

The problem

github_actions() builds the URL with a template literal over two environment variables that may be undefined:

"url": `https://github.com/${process.env.GITHUB_REPOSITORY}/actions/runs/${process.env.GITHUB_RUN_ID}`,

Interpolating undefined yields the literal string "undefined", so the result is:

https://github.com/undefined/actions/runs/undefined

That is a real string rather than undefined, so JSON.stringify keeps it and it is sent as though it were a genuine URL.

Why it is reachable

ci_env() enters this branch on GITHUB_RUN_NUMBER alone:

} else if (process.env.GITHUB_RUN_NUMBER !== undefined) {
  return(this.github_actions())

Neither GITHUB_REPOSITORY nor GITHUB_RUN_ID is checked. The existing test uses github action environment variables second already walks this exact path — it sets only GITHUB_RUN_NUMBER — but it asserts only on ci, so the malformed URL goes unnoticed.

Reproduced against the current code:

process.env.GITHUB_RUN_NUMBER = '43'
new CI().env('jest').url
// 'https://github.com/undefined/actions/runs/undefined'

Why the other branches are fine

buildkite() and circleci() assign process.env values directly, so a missing variable stays undefined and JSON.stringify drops the key. This brings github_actions() in line with them.

Tests

Added a regression test that fails on the current code — Received: "https://github.com/undefined/actions/runs/undefined" — and passes with the change. Suite: 10 passed.

One thing I left alone

key has the same shape and produces undefined-43-undefined when GITHUB_ACTION and GITHUB_RUN_ATTEMPT are absent. I did not touch it because key is required and changing its format could affect how runs are grouped on your side. Happy to follow up if you would like it handled.