Lint Tool

We have a lint tool for catching common mistakes in test files. You can run it manually by running the wpt lint command from the root of your local web-platform-tests working directory like this:

./wpt lint

The lint tool is also run automatically for every submitted pull request, and reviewers will not merge branches with tests that have lint errors, so you must either fix all lint errors, or you must whitelist test files to suppress the errors.

Fixing lint errors

You must fix any errors the lint tool reports, unless an error is for something essential to a certain test or that for some other exceptional reason shouldn’t prevent the test from being merged; in those cases you can whitelist test files to suppress the errors. In all other cases, follow the instructions below to fix all errors reported.

Updating the whitelist

Normally you must fix all lint errors. But in the unusual case of error reports for things essential to certain tests or that for other exceptional reasons shouldn’t prevent a merge of a test, you can update and commit the lint.whitelist file in the web-platform-tests root directory to suppress errors the lint tool would report for a test file.

To add a test file or directory to the whitelist, use the following format:

ERROR TYPE:file/name/pattern

For example, to whitelist the file example/file.html such that all TRAILING WHITESPACE errors the lint tool would report for it are suppressed, add the following line to the lint.whitelist file:

TRAILING WHITESPACE:example/file.html

To whitelist an entire directory rather than just one file, use the * wildcard. For example, to whitelist the example directory such that all TRAILING WHITESPACE errors the lint tool would report for any files in it are suppressed, add the following line to the lint.whitelist file:

TRAILING WHITESPACE:example/*

Similarly, you can also use shell-style wildcards to express other filename patterns or directory-name patterns.

Finally, to whitelist just one line in a file, use the following format:

ERROR TYPE:file/name/pattern:line_number

For example, to whitelist just line 128 of the file example/file.html such that any TRAILING WHITESPACE error the lint tool would report for that line is suppressed, add the following to the lint.whitelist file:

TRAILING WHITESPACE:example/file.html:128