feat: single file HTML report

[bartekleon]

Output the index.html file without the need for external resources. This will make using it in CI/CD pipelines.

With this, you can simply open the index.html file in your browser, without first needing to extract all files to a directory. This will also make Stryker compatible with the azure-devops-mutationreport-publisher.

If you were relying on the reports/mutation/html/bind-mutation-test-report.js file containing the report JSON, please migrate to the new JSON reporter: https://stryker-mutator.io/docs/stryker/configuration#reporters-string

fixes: #2188

[bartekleon]

adds single file report alongside existing one. I guess it should be tested(?), but still for now it's only proof of concept (image is still standalone file tho! :P [but honestly who cares about image if it doesn't load ;x])

[nicojs]

An image can be added with a data-url. Or we can use our new svg: https://stryker-mutator.io/images/stryker.svg

[nicojs]

Thanks for picking this up!

[nicojs]

I'm actually thinking that we should add this with a configuration option. For big projects, it's kind of a waste to have 2 reports for each run, since file size can rise significantly.

@simondel what is your take on this?

1. Make it configurable?
2. If so. what will the default be? What will the configuration option name be? htmlReporter.singleFile?
3. If not: force both? Or only 1?

[bartekleon]

In any case, unfortunatelly I have very little time during next two weeks or so. Mostly university stuff + personal problems, so if you could carry on this issue from this point :)

[HonzaMac]

I would prefer to have only one index.html with all-in-one.

[nicojs]

@kmdrGroch I'm finishing this one. Want to get it in the 4.3 release 😍