chore(code coverage): enable coverage remapping to source via sourcemap

[kwonoj]

• update script enables test coverage remapping to original (es6) source
• minor update to document, code

This PR introduces remap-istanbul module allows to remap test coverage into original source code instead of transpiled results. (istanbul side discussion is ongoing at gotwarlost/istanbul#212) Due to current build processes, this PR does not resolves remapping issue fully though.

[kwonoj]

Found cjs / es6 modules didn't have sourcemap until now..

[kwonoj]

It is expected to see coverage number is decreased with this PR, now coverage is completely recalculated with ES6 output due to remapping. When it comes to original typescript source, I could observe coverage is around ~85%.

[benlesh]

This looks great so far. Unsure when I'll get a chance to merge this though. Might be a few days.

[kwonoj]

Take your time, PR'll be there when you're back :) If I could find solutions of converting sourcemaps, I'll update PR meanwhile

[benlesh]

Also we'll have to research getting coveralls to be more lax until we're out of alpha

[kwonoj]

@Blesh I could find this in coverall repo setting, maybe this is way to control? (Seems only repo owner can change those values)

[kwonoj]

PR's updated including one additional commit to close #558, now cover generates multi stage sourcemap pointing to original source. As same as original commit, it is expected to see coverage goes down compare to coverage against commonjs based source codes. You may able to check coverage report at https://coveralls.io/builds/3890453

I was originally tried to suggest move into different build system other than simple npm scripts, but found out that changes will include amount of out-of-scope changes not related with this specific issue. Those can be discussed in further as long term goal, focused to resolve immediate issue first.

[benlesh]

Okay, I've temporarily increased thresholds of Coveralls to allow this to merge without breaking Travis. We'll see if it works.

[benlesh]

@kwonoj so I pulled down this PR, rebased on master, removed node_modules, reinstalled via npm, and ran npm run build_cover and it runs fine right to the end, and I get an error when it calls:

node lib/stage_sourcemap.js && remap-istanbul -i coverage/coverage.json -o coverage/coverage-remapped.json && remap-istanbul -i coverage/coverage.json -o coverage/coverage-remapped.lcov -t lcovonly && remap-istanbul -i coverage/coverage.json -o coverage/coverage-remapped -t html

Error:

Error: Cannot find module 'jsonfile'
    at Function.Module._resolveFilename (module.js:336:15)
    at Function.Module._load (module.js:278:25)
    at Module.require (module.js:365:17)
    at require (module.js:384:17)
    at Object.<anonymous> (/Users/blesh/GitHub/blesh/RxJS/lib/stage_sourcemap.js:3:16)
    at Module._compile (module.js:460:26)
    at Object.Module._extensions..js (module.js:478:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Function.Module.runMain (module.js:501:10)

I'll look into it, but not for too long, I have a LOT of PRs to catch up on. :)

[kwonoj]

Seems I mistakenly miss one of dependencies. I'll try to resolve on my side and update PR.

[benlesh]

@kwonoj great! Notify me when you've got it. (Both here and Twitter today, because my GH inbox is dead from last week).

[benlesh]

Travis doesn't seem to be running the check now... this line is suspect.

[kwonoj]

Yes, I'm looking those part now. On my forked branch this works, failed here, continuing investigation.

[benlesh]

Also, it seems that remap-istanbul isn't writing a coverage-remapped.lcov file at all.

[kwonoj]

I will push some dummy commits to analyze logs, will flatten them once issue is resolved. Will notify you @Blesh separately once it's done.

[kwonoj]

OK, travis & coveralls both happy. Reason of failures was jsonfile module has unexpected regression on latest 2.2.3 version, pinned down into 2.2.2 as known good. Dummy commits are flattened.

[benlesh]

merged with 69aa51d ... thanks for all of that @kwonoj! That was a tricky bit of work you did there.