Bazel + Jest: Dynamic location for jest-junit's xml file

[daivinhtran]

As mentioned in #34 (comment), when we run jest with Bazel, the tests are run in a test sandbox and the directory to the sandbox is not deterministic until the execution phase.

When bazel runs jest, bazel writes test.xml differently from jest-junit. test.xml (generated by bazel) is in written in
/private/var/tmp/[computer_name]/[unconsistent_hash]/execroot/[workspace_name]/bazel-out/darwin-fastbuild/testlogs/package_name/jest/test.log while jest-junit writes to a folder defined by the config or JEST_JUNIT_OUTPUT_DIR env var.

The path to the testlogs (e.g. XML_OUTPUT_FILE) isn't defined until jest is executed by bazel. So we don't know the value to pass in JEST_JUNIT_OUTPUT_DIR or the config statically.

It would be great if we can pass in a global variable name for jest-junit to look at runtime. Something like

"jest-junit": {
  "outputName": "env_var:JEST_JUNIT_OUTPUT_DIR"
}

I'm happy to put up a PR for the proposed feature if you think it's a good idea.

[palmerj3]

Hey! Thanks for raising this issue.

I'd be happy to accept a PR contribution that adds this functionality.

Just curious wouldn't you be able to make use of jest-junit's environment variable to make this work?

JEST_JUNIT_OUTPUT_DIR="$XML_OUTPUT_FILE" jest

[daivinhtran]

Thanks @palmerj3 for the quick response.

I found out bazelbuild's rules_nodejs recently added the env attribute to do what you just described above.
PR: bazel-contrib/rules_nodejs#2499
Issue: bazel-contrib/rules_nodejs#2497

However, we still need another config like JEST_JUNIT_OUTPUT_FILE instead of JEST_JUNIT_OUTPUT_DIR or JEST_JUNIT_OUTPUT_NAME because XML_OUTPUT_FILE (set by bazel) is the full path to the xml file instead of just the directory.

We need the full path (dir + filename) to be dynamic because bazel has the capability to retry on flaky tests. Each retry produces a different xml filepath and we need to store and process all the xmls (both failed and passed attempts) to get better reporting on flaky tests.

So given that rules_nodejs added the env attribute to let us set environment variable, we don't need to implement what I originally propose. Instead, we will add JEST_JUNIT_OUTPUT_FILE to accept the fullpath to the xml file. When this config is used, JEST_JUNIT_OUTPUT_DIR and JEST_JUNIT_OUTPUT_NAME will be overriden.

JEST_JUNIT_OUTPUT_FILE="$XML_OUTPUT_FILE" jest

Please let me know if anything is not clear.

[daivinhtran]

Hi @palmerj3 . Please take a look whenever you have a chance. #168. Thank you.

[palmerj3]

Thank you!

I just published https://github.com/jest-community/jest-junit/releases/tag/v12.1.0 with your changes included.