Switch to karma

[wvanderp]

TLDR: I replaced phanton.js with karma and fixed the tests.

In this PR, I changed phatom.js for karma and fixed the newly failing tests.

What follows is a long list of changes:

• Added karma test runner
• Removed phantom.js
• Removed the polyfills for phantom.js
• Replace the homegrown fake fetch for a module
• Implemented code coverage and ignored them in git and npm
• Fixed the issues caused by replacing the fake fetch
• updated all test-related packages

There are also some remarks and issues:

• some of the tests fail when the tests are run in a windowed environment. but not in a headless environment
• This PR makes it difficult to run tests on IE11 because it does away with some of the polyfills.
  • On the other hand, you can select IE11 as a runner, so we can always add that back later.
• This is a large change, and I am new to developing for ID, so this change should be tested both in development environments and CI to gain confidence in the change.
• I didn't edit any of the documentation or code added for phantom.js

sorry for all the white space changes it seems that these files were not touched for a long time.

I am happy to answer any questions or make any changes to this commit.

[wvanderp]

I don't know what to do about the failing build on node 10. I can reproduce because I encounter another problem while installing.

but some of our dependencies like @ideditor/country-coder, @ideditor/location-conflation, or osm-community-index don't support 10

[jfirebaugh]

Thanks @wvanderp!

Could you please revert the stylistic and whitespace changes? Those make it more difficult to review and would clutter git history/git blame.

[wvanderp]

Sorry for the potential spam. I had to remove the formatting by hand and it didn't want to be removed.

But it is gone now.

I would advise to introduce some rules for committing the changes.

[mbrzakovic]

@wvanderp big thanks for this contribution!
Could you please just shortly state what are the core gains for replacing phantom with karma?

[wvanderp]

TLDR: maintainability and flexibility

Gains in maintainability:

The main reason is that PhantomJS is depricated.
See #7697

Karma is a large ecosystem, and because of this, we gain a more stable future for our test runner and a lot of support online.

After some tweaking of the config files, it is possible to debug karma test with the chrome dev tools.

Gains in flexibility:

Because of Karmas large ecosystem, we can get a lot of new functionality out of the box.

There are plugins for most browsers under the sun. I currently only choose chrome because it is the most straightforward. But with some modifications (mainly removing es6 and adding polyfills), we can use IE11 or even PhantomJS as our runner.

I have configured karma to collect test coverage. I think this is new for the project. Also a bit difficult to add to the old setup.

[tyrasd]

This PR makes it difficult to run tests on IE11 because it does away with some of the polyfills.

See #8774 (comment), this is not really an issue for us anymore. 😉

[tyrasd]

Thanks for this very useful switch @wvanderp!

I don't know what to do about the failing build on node 10

this was resolved in the meantime with #8766

I didn't edit any of the documentation or code added for phantom.js

I merged this more or less as is, such that work on #8774 (or #8811) isn't blocked anymore. I only removed the old "test runner" index.html for phantomjs for now, but there are quite a few remaining bits of codes referencing phantomjs around and, as you said, the documentation probably also needs to be updated. Let's track that in a separate ticket -> #8843.