Run Emscripten tests in a browser

[mcbarton]

Description

Please include a summary of changes, motivation and context for this PR.

This PR adds the ability to run the Emscripten tests in a browser

Fixes # (issue)

Type of change

Please tick all options which are relevant.

• Bug fix
• New feature
• Added/removed dependencies
• Required documentation updates

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.78%. Comparing base (53d1686) to head (98dd563).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #294   +/-   ##
=======================================
  Coverage   81.78%   81.78%           
=======================================
  Files          20       20           
  Lines         950      950           
  Branches       87       87           
=======================================
  Hits          777      777           
  Misses        173      173           

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[mcbarton]

Running the tests makes use of emrun which comes with Emscripten. The documentation for emrun can be found here https://emscripten.org/docs/compiling/Running-html-files-with-emrun.html

[anutosh491]

Hey @DerThorsten

I would really appreciate your expertise here. Please let us if this should be our GoTo method to address the problem statement here.

The contributor has made quite some comments describing his approach here.

Feel free to let us know if we can do better. Thanks !

[vgvassilev]

IIRC, @mcbarton mentioned he discussed that at the emscripten discord or similar.

[mcbarton]

emscripten-core/emscripten#24273 - This is where I discussed it previously with Emscripten maintainers. I asked the Emscripten maintainers about this PR, and they said that emrun is a reasonable way to run Emscripten tests in a browser, and that my emrun command looks reasonable.

[mcbarton]

I've added the PR comments, as comments in the files as requested here #294 (comment)

[mcbarton]

@anutosh491 pinging you on this PR, since you said it would go in by the end of today in the Discord chat with @vgvassilev

[vgvassilev]

Lgtm!

[anutosh491]

pinging you on this PR,

Writing my thoughts.

[mcbarton]

@vgvassilev It was my understanding that it had already been decided on our Discord group chat that this would go in today. Are you happy for me to merge this, and I can deal with any of any @anutosh491 thoughts post merge, or would you like me to wait?

[anutosh491]

Hey @SylvainCorlay ,

I went through this PR today and I don't have any strong opinions here (probably I'm not educated enough or falling short on time to educate myself with all going on here)

I tagged @DerThorsten couple days back but haven't heard from him.

So do you have any opinions if this is how we should test stuff in the browser ?
I'll let you move this in if you think we're good (Vassil says we're good)

Some surface level reviews

1. Not a fan of having explanations/long writeups in the actions file. If at all I would like references/docs than explanation for some thing. If in question we can get back to the PR as to why something was done. We all probably lack experiences that a technical writer would have, so framing explanations more than a couple lines is not really what I'd prefer.

2. Not a fan of having users follow a huge set of instructions in the readme for building/testing (1 configure command, 1 build command, 1 test command is all I would follow). If at all we want to provide a huge set of instructions for testing ....... I've seen quite some repos just put all of it in a build script and ask the user to run the build script (like ./build_xeus_cpp_test.sh)

EDIT : Also after build and install, running jupyterlite comes way below (I would like a user to try lite first, then test stuff if they really want to, let's have the complete build workflow first and then have the test workflow ?)

That being said, these are just my thoughts. If anyone thinks otherwise and can't wait on this, feel free to move it in.

[SylvainCorlay]

For in-browser testing, my initial thought was that we could use Galata for full integration tests with Jupyter, including visual non-regression tests, but I like this approach of running the standard C++ tests in the browser with emrun.

Galata-based integration tests could be added at a later stage, including for the native builds.