Magic assert doesn't seem to work with "type": "module"

[Filyus]

Just add "type": "module" to package.json and run the failing test in ES-module, you don't see any code in the logs. I don't want to install something like Babel.
ava 3.15.0
Node 12.20.0

test.js:

import test from 'ava';
test("test magic assert", t => {
  t.is(1, 2); 
});

log:

  test magic assert

  Difference:

  - 1
  + 2

  » file:///test.js:3:5

  ─

  1 test failed

Related: #2293

[novemberborn]

It strikes me that the path is file:///test.js which implies the test file was at your file system's root. That seems odd. Assuming the file does not actually live there, this is probably the error.

I haven't had a chance yet to try and reproduce this but it's on my radar.

[novemberborn]

I suspect the problem is here:

ava/lib/serialize-error.js

Lines 25 to 34 in b8f5685

	// Normalize the test file so it matches `callSite.file`.
	const relFile = path.relative(process.cwd(), testFile);
	const normalizedFile = process.platform === 'win32' ? slash(relFile) : relFile;
	for (const line of stack.split('\n')) {
	const callSite = stackUtils.parseLine(line);
	if (callSite && callSite.file === normalizedFile) {
	return {
	isDependency: false,
	isWithinProject: true,
	file: path.resolve(process.cwd(), callSite.file),

I haven't tested it directly, but this came up in my work for #2741.

[ghost]

@novemberborn not sure if it is fixed by #2741. I encountered the same issue today and tried with the master branch. The issue is still reproducible. Same setup as @Filyus, "type": "module" in package.json and everything as es modules.

[ghost]

hmm maybe it's because of the source maps, the files are compiled from typescript and the source maps point to .ts files.

[ghost]

well, forgive my ignorance @novemberborn. Just found out that I would need additional configuration to work with precompiled typescript.

[ghost]

unfortunately, es modules do not work with the @ava/typescript yet.

I was curious though. My setup has IDE watchers that auto compile the typescript to javascript in the same folder on change. This was a nice setup for me because I can use these auto transpiled codebase directly as the artifact without needing a bundle (at least in dev). I expected the same to work for avajs such that I just reference the transpiled test files and the source maps help with the stack traces.

I was playing with the codebase and seems it works if the check to match stack trace with the test file does not check the extension strictly. I think this would work nicely even if the js is transpiled to another folder, given that source maps are generated during transpile. Find the change I made to try this in screenshot below, I basically changed line 40 to line 41 in serialize-error.js. It loads the files properly and generates the magic asserts with correct trace based on the sourcemap.

Do you think this could be something that can be supported, maybe under a configuration flag or so? @novemberborn I think all of the typescript projects that do not bundle should work with this approach without needing @ava/typescript, just if the transpiled files go into another folder, it would be more than just checking the filename without extension.

[novemberborn]

unfortunately, es modules do not work with the @ava/typescript yet.

If you're game @jiby-gh, it shouldn't be too hard to implement, see avajs/typescript#5 (comment).

Do you think this could be something that can be supported, maybe under a configuration flag or so?

I don't quite follow, sorry. What is your suggestion?