Technical discussion: Manual testing

[jkup]

I'm hoping we can use this issue to begin discussing approaches to manually testing source maps.

• @kamilogorek made this great playground Test Suite for Source Maps  ecma426#15
• For both manual and automated test discussions, we should enumerate a list of implementations (see List source map implementations ecma426#47)
• @mitsuhiko Did some awesome research into "column" definition's here Tighten the definition of "column" ecma426#5 (comment)

[jkup]

Also might be worth mentioning these two online tools for exploring source maps:

1. https://evanw.github.io/source-map-visualization/
2. https://sokra.github.io/source-map-visualization/

[kamilogorek]

Link no 1 from the initial post should link to https://github.com/kamilogorek/sourcemaps-playground :)
There's also https://github.com/kamilogorek/sourcemaps-headers now which can be used to validate headers precedence over inlined pragma.