setup code coverage

[ssube]

Summary

Typescript and Istanbul have issues (microsoft/TypeScript#24993) working together, but the nyc tool should support source maps if they have the correct paths.

Scope

• make target
  • instrument with nyc
  • execute test bundle with instrumented main bundle
  • exclude node_modules and out, include src and test
  • gather test results
• source maps
  • ext file for each bundle
  • correct path in bundle
  • istanbul/nyc load maps
  • include in npm bundle
• upload results to code climate
  • token
  • tool image (if necessary)
  • pipeline job
• set up codecov
  • repo setup
  • token
  • upload job
  • github required check

Use Case

Feature-driven tests are great, but coverage shows you dead code. To keep the bot lean as it grows, comprehensive tests and aggressive removal of unused code is vital.

Issues

Huge time sink, but very useful.

[ssube]

Current test harness only includes files from src/ with some test coverage, leaving most of them out :( and skewing results too high :( . Either the --all argument to nyc or including src via webpack context should work, but node_modules and the out stubs still need to be excluded.

Until istanbuljs/nyc#953 is resolved, including sources leads to node_modules being instrumented, which runs indefinitely.

[ssube]

Working for now with the written tests and their included sources, but nyc itself is still including node_modules. Following up in their issues, using sed as a workaround to remove modules and webpack extras from lcov report before uploading. CI is set up with coverage, but numbers are high (not all src is included, only that imported by tests).