Coverage docs

[Toxicable]

So we need some docs for coverage.
For now I'll update this issue as the docs, once I've finalized it I'll add a MR to into the docs site.

Config

.bazelrc

# When running `bazel coverage` --instrument_test_targets needs to be set in order to
# collect coverage information from test targets
coverage --instrument_test_targets

WORKSPACE
If you use included_files then ensure that .wasm is added
If you don't use included_files then this isn't needed

yarn_install(
  ...
  included_files = [ ".wasm" ] 

Targets
Any target that you'd like to enable coverage for needs to add "@npm//c8" as a dep.

jasmine_node_test(
  ...
  deps = [ "@npm//c8" ]

Tracking issues

• Incorrect paths of coverage files Coverage paths include incorrect ../../../ path prefix #2376
• Enabling "all: true" option in c8 Coverage should include all: true option from c8 #2377

Development

Basic run
Run yarn bazel coverage --combined_report=lcov --experimental_convenience_symlinks=normal :target
The combined lcov report will be in bazel-out/_coverage/_coverage_report.dat

Tracking issues

• ibazel coverage support Support ibazel coverage bazelbuild/bazel-watcher#448
• Coverage Gutters watch
• Symlink only coverage file

CI

[herman-rogers]

Does this rule work with karma_web_test_suite? As in can I run bazelisk coverage for karma rules and have it output correct coverage?

[github-actions]

This issue has been automatically marked as stale because it has not had any activity for 90 days. It will be closed if no further activity occurs in two weeks. Collaborators can add a "cleanup" or "need: discussion" label to keep it open indefinitely. Thanks for your contributions to rules_nodejs!

[github-actions]

This issue was automatically closed because it went two weeks without a reply since it was labeled "Can Close?"

[farcaller]

It doesn't seem to work with e.g. jest (based on the jest example) – there's no coverage data generated after the run.