test_runner: directory arguments to --test fail with MODULE_NOT_FOUND on Windows (regression since v20)

[dhruvvv0913]

Version

test_runner: directory arguments to --test fail with MODULE_NOT_FOUND (regression since v20, all platforms)

Platform

Microsoft Windows NT 10.0.26200.0 x64

Subsystem

test_runner

What steps will reproduce the bug?

Create a directory containing a single test file:

tests/sample.test.mjs:

import test from 'node:test';
test('ok', () => {});

Then, on Windows, pass the directory to the test runner:

node --test tests
node --test tests/
node --test tests\

All three fail with MODULE_NOT_FOUND — the directory is executed as if it
were a test file instead of being searched for test files.

For contrast, all of the following work:

• node --test with no arguments in the same folder (default discovery finds and runs the test)
• the same three commands on Node v20.20.2 on Windows
• passing a directory on Linux/macOS

How often does it reproduce? Is there a required condition?

Always, on Windows, whenever a directory path is passed as an argument to --test.

What is the expected behavior? Why is that the expected behavior?

Passing a directory to node --test should recursively search it for test
files and run them, as documented, as Node v20 does on Windows, and as current
versions still do on Linux/macOS.

What do you see instead?

The directory is treated as a single test file and executed directly, which
fails in the module loader:

PS C:\Users\KIIT\node-bug-repro> node --test tests/
node:internal/modules/cjs/loader:1368
  throw err;
  ^

Error: Cannot find module 'C:\Users\KIIT\node-bug-repro\tests'
    at Function._resolveFilename (node:internal/modules/cjs/loader:1365:15)
    at defaultResolveImpl (node:internal/modules/cjs/loader:1021:19)
    at resolveForCJSWithHooks (node:internal/modules/cjs/loader:1026:22)
    at Function._load (node:internal/modules/cjs/loader:1175:37)
    at TracingChannel.traceSync (node:diagnostics_channel:322:14)
    at wrapModuleLoad (node:internal/modules/cjs/loader:235:24)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:171:5)
    at node:internal/main/run_main_module:36:49 {
  code: 'MODULE_NOT_FOUND',
  requireStack: []
}

Node.js v22.18.0
✖ tests (70.2044ms)
  'test failed'
ℹ tests 1
ℹ suites 0
ℹ pass 0
ℹ fail 1
ℹ cancelled 0
ℹ skipped 0
ℹ todo 0
ℹ duration_ms 79.0802

✖ failing tests:

test at tests:1:1
✖ tests (70.2044ms)
  'test failed'

The output is identical for node --test tests and node --test tests\.

Additional information

This appears to be a regression between v20.20.2 (works) and v22.x (broken).
Possibly related to the test runner's file discovery moving to the internal
glob implementation (createTestFileList in lib/internal/test_runner/runner.js),
where a directory pattern seems to match the directory itself rather than
being expanded to the test files inside it.

Happy to work on a fix if a collaborator confirms this is a bug.

[dhruvvv0913]

Update after more digging — this is not Windows-specific; I've updated the title.

I retested on Linux x64 (Ubuntu 24.04 via WSL2, official v24.18.0 binary):
node --test tests fails the same way. My "works on Linux/macOS" note in the
original report was wrong.

The root cause appears to be the v20 → v22 change in test file discovery:

• v20: processPath() calls statSync() and recursively walks directories
  with readdirSync(), so directory arguments worked:
  https://github.com/nodejs/node/blob/v20.20.2/lib/internal/test_runner/runner.js#L91-L126
• v22+: discovery moved to the internal glob in createTestFileList():
  https://github.com/nodejs/node/blob/v22.18.0/lib/internal/test_runner/runner.js#L108-L126
  A pattern that literally matches a directory returns the directory path
  itself (standard glob semantics — no expansion), and the runner then spawns
  it as if it were a test file, which crashes with MODULE_NOT_FOUND.

Worth noting: the v20 docs explicitly documented directory arguments, with a
directory in the example (node --test test1.js test2.mjs custom_test_dir/ —
"The test runner will also recursively search the directory"):
https://github.com/nodejs/node/blob/v20.20.2/doc/api/test.md
Current docs mention only glob patterns, but there was no deprecation cycle or
clear error — scripts using the documented form went from working to a cryptic
crash.

Proposed fix: in createTestFileList(), when a user-supplied pattern has no
glob magic and stats to a directory, expand it to <pattern>/<kDefaultPattern>
before matching — restoring the documented v20 behavior while keeping the glob
implementation. Alternatively, if directory support is intentionally dropped, a
clear error message would at least remove the confusing crash. Happy to open a
PR either way.