Use AppVeyor for karma/jasmine CI testing on IE11

[etpinard]

... and maybe on MS Edge too, down the road.

I've made some prelim. work on the appveyor branch where karma-ie-launcher is used to boot up IE.

Issues that I've ran into

• all our tests that use our mouseEvent wrapper are failing (because window.mouseEvent does not work in IE11, see prelim attempt for writing a wrapper here)
• I had to use npm install --force so that node-sass installs properly run after run. This has the side effect of making our AppVeyor test runs > 10 minutes long. We have to find a better way of caching packages.

Full CI outputs: https://ci.appveyor.com/project/etpinard/plotly-js/build/7

Any help from anyone with access to a Windows machine and/or with AppVeyor expertise would be greatly appreciated.

[mdtusz]

Interesting. Why was/is the node-sass installation failing?

We should probably add

cache:
  - %PATH_TO_PLOTLYJS%\node_modules
  - %PATH_TO_PLOTLYJS%\npm-cache

to the appveyor.yml though.

[etpinard]

Interesting. Why was/is the node-sass installation failing?

I got some Error: EPERM: operation not permitted off this build. This error apparently has happened to other folks (e.g. here).

[etpinard]

@antoinerg would be interesting in taking this one?

My 3-year old attempt is here -> https://github.com/plotly/plotly.js/tree/appveyor (not sure if it'll be useful though)

cc @nicolaskruchten

[etpinard]

Note, we don't have to run all our jasmine tests there. Most of our pixel-based-assertions will probably fail, getting those up-to-speed for IE will be too much of a pain for little gain. We could either tag a few existing tests with a new @IE tag or add a seperate suite.