How to include files completely missing tests from coverage reports?

[swantzter]

Node.js Version

v22.9.0

NPM Version

v10.8.3

Operating System

Linux razz 5.15.153.1-microsoft-standard-WSL2 #1 SMP Fri Mar 29 23:14:13 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

Subsystem

Other

Description

If I have two files, add.js and subtract.js along with tests for just one of them add.test.js which imports add.js I would like the --experimental-test-coverage to report that I have only tested 50% of files.

I've tried using --test-coverage-include='*.js' but this does not seem to include the additional files, I've also tried changing the test pattern node --test *.js which does seem to sort-of work, but it adds extra processing for every file (~1s per file) and logs it as a test suite file in the console, which is undesirable.

Is there a way to make sure coverage reports across all files with a given pattern?

Minimal Reproduction

https://github.com/swantzter/poc-node-test-coverage

Output

Given the three files above, run node --test --experimental-test-coverage --test-coverage-include='*.js' --test-coverage-exclude='*.test.js'

This prints

[...]
# -------------------------------------------------------
# file   | line % | branch % | funcs % | uncovered lines
# -------------------------------------------------------
# add.js | 100.00 |   100.00 |  100.00 | 
# -------------------------------------------------------
# all f… | 100.00 |   100.00 |  100.00 |
# -------------------------------------------------------
# end of coverage report

I would expect, or am trying to find a way to make it print

[...]
# ------------------------------------------------------------
# file        | line % | branch % | funcs % | uncovered lines
# ------------------------------------------------------------
# add.js      | 100.00 |   100.00 |  100.00 |
# subtract.js |   0.00 |     0.00 |    0.00 | 1-3
# ------------------------------------------------------------
# all files   |  50.00 |    50.00 |   50.00 |
# ------------------------------------------------------------
# end of coverage report

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[swantzter]

Yes that does work but the runtime gets significantly worse and the logged output gets less useful

[nullswan]

Related: https://github.com/orgs/nodejs/discussions/55447