Debug.logs aren't shown if a test hangs

[MartinSStewart]

I've noticed that the Debug.log messages aren't shown until the tests are completed. Unfortunately this means that if I have a test that hangs I need to kill the test runner and then I never see the Debug.logs. Is there a way to handle this situation?

[mpizenberg]

Hum, currently, calls to the log function accumulate in an array, which is transferred to the reporter and cleared everytime a test finishes:

elm-test-rs/templates/node_runner.js

Lines 38 to 40 in 54920e1

	msg.logs = logs;
	parentPort.postMessage(msg);
	logs.length = 0;

I haven't really thought if there could be a way to stream the logs in addition to accumulate them, or if that's desirable. If you need unblocking, after having compiled once, you can modified these line in the file elm-stuff/tests-0.19.1/js/node_runner.js of your project.

[mpizenberg]

Actually (I just checked now) and that file gets overwritten on next elm-test-rs call. So what you'd need to do after one call of elm-test-rs is emulating the final call yourself. So the steps are:

1. Call elm-test-rs once (kill it if it fails, we only care about the compiled artifacts)
2. Inside elm-stuff/tests-0.19.1/js/node_runner.js, replace console.elmlog = (str) => logs.push(str + "\n"); by

console.elmlog = (str) => {
  console.error(str);  // uses stderr stream because stdout stream is not piped to elm-test-rs main
  logs.push(str + "\n");
};

3. cd inside elm-stuff/tests-0.19.1/js/ and call echo "./node_runner.js" | node node_supervisor.js

Sorry for the inconvenience.

[MartinSStewart]

I was able to solve the issue but this is good to know if I run into it again.

Sorry for the inconvenience.

No worries. This tool on the whole more than makes up for this slight inconvenience 👍