Test runner: recursive or globbed loading of non-JS test files

[meyfa]

What is the problem this feature will solve?

As per https://nodejs.org/dist/latest-v18.x/docs/api/test.html#test-runner-execution-model, the test runner can be started as node --test dirname/ to recursively run all test files (ending in .js, .cjs or .mjs) contained in the directory dirname. This unfortunately means that non-JS test files, specifically test files written in TypeScript in my case, will not be found since they end in .ts instead of .js. The docs say to provide each test file separately, e.g. node --loader=ts-node/esm --test dirname/foo.test.ts dirname/bar.test.ts but this gets messy very quickly.

What is the feature you are proposing to solve the problem?

I see a few options (in order of my preference, starting with most preferred):

• Support globbing (e.g., node --loader ts-node/esm --test "dirname/**/*.ts"). Note that this does work on Linux, to some extent, since the shell will expand asterisks. This doesn't work on Windows, though, and doesn't work when the string is quoted. Tools like mocha will perform globbing independently of the operating system or shell.
• Provide a CLI arg for additional test file extensions (e.g., node --loader ts-node/esm --test --test-extensions=.ts,.cts,.mts dirname/).
• Have some sort of configuration file for the test runner where this can be configured.
• Let loaders tell Node about additional file extensions (e.g., node --loader ts-node/esm --test dirname/ and ts-node could hook into the directory traversal).

What alternatives have you considered?

• Listing test files manually (hard to maintain)
• Having a script do the globbing and construct the command line with all files explicitly listed
• Running node --test pointed to an index file that performs the globbing and dynamically imports all actual test files (very ugly; loses process separation between test files)

I also opened an issue at ts-node (TypeStrong/ts-node#1853) specifically for TypeScript, to see if they are interested in better test runner support.

[benjamingr]

@nodejs/test_runner

[benjamingr]

Honestly, I would just add .ts support explicitly (and probably .tsx/.jsx) given how common it is compared to the alternative with a helpful message in case people didn't pass a loader/require hook.

[MoLow]

probably for starters, as @benjamingr support /.tsx?$/ as well,
eventually allow configuration of custom file filtering

[ljharb]

I don’t think supporting ts (or jsx) by default makes any sense if TS/JSX content isn’t auto loaded.

[MoLow]

Perhaps we should implement a solution for #43895 (that will allow passing a custom function to filter files)

I am willing to implement some --test-config flag if there is consensus on it.
CC @nodejs/test_runner

[aduh95]

Maybe a better solution would be to have an option for the loader to have an option to tell which file patten it supports for tests? /cc @nodejs/loaders

[MoLow]

Maybe a better solution would be to have an option for the loader to have an option to tell which file patten it supports for tests?

why will it be better? I think a configuration file will cover more use-cases (real usecases from here), for example:

• within a file, filter which tests should run
• support glob (without relation to ts support)

loaders should process test files regardless of this discussion, there is a seperate issue about that

[aduh95]

Running the test runner on a .ts file only makes sense if there's a loader able to understand it, so it's convenient if the loader itself can provide this info. If the info comes from somewhere else, it's more likely to de-sync at some point. Anyway that was just a thought.

[ljharb]

I completely agree that that’s the only way to handle it. Nothing should be implicitly included unless node understands it;cams adding a loader should also implicitly include anything the loader handles. Users should only have to configure file extensions if they’re deviating from their loaders’ defaults.

[MoLow]

I might not fully understand how loaders work, so correct me in case I am wrong - a loader does not expose what file extensions it supports,
So there is no way for --test to know what to extensions to filter
If we are talking about a new flag/option declaring what extensions a loader supports in the context of running tests - I don't really see a reason that should be part of loaders and not just part of the test runner config?

[meyfa]

Personally, I see a huge advantage in letting users specify the file pattern precisely: I often find myself putting test fixtures, shared code etc. in the test/ directory (e.g. test/fixtures.ts), along with test files (such as test/foo.test.ts, test/bar.test.ts). In these cases, I would want to use a glob like test/**/*.test.ts instead of basing it off of the .ts extension.