The coverage reporter for the console has been changed from `text` to
`text-summary` because `text` was too long. It exceeded the maximum
length of the CircleCI terminal output shown on their jobs page, making
it very difficult to see why the unit test coverage job failed.
The text summary only displays overall coverage metrics, but that is
usually enough to indicate when the test fails due to a drop in
coverage. The more detailed breakdown is still available as a HTML
report linked in the `metamaskbot` comment, and in the `jest-coverage`
directory when run locally.
The three on-disk coverage reports used previously (`lcov`, `json`, and
`clover`) have been replaced with just `html`. The HTML report was part
of the `lcov` report, and it was the only one we were using.
This PR adds build-time code exclusion by means of code fencing. For details, please see the README in `./development/build/transforms`. Note that linting of transformed files as a form of validation is added in a follow-up, #12075.
Hopefully exhaustive tests are added to ensure that the transform works according to its specification. Since these tests are Node-only, they required their own Jest config. The recommended way to work with multiple Jest configs is using the `projects` field in the Jest config, however [that feature breaks coverage collection](https://github.com/facebook/jest/issues/9628). That being the case, I had to set up two separate Jest configs. In order to get both test suites to run in parallel, Jest is now invoked via a script, `./test/run-jest.sh`.
By way of example, this build system feature allows us to add fences like this:
```javascript
this.store.updateStructure({
...,
GasFeeController: this.gasFeeController,
TokenListController: this.tokenListController,
///: BEGIN:ONLY_INCLUDE_IN(beta)
PluginController: this.pluginController,
///: END:ONLY_INCLUDE_IN
});
```
Which at build time are transformed to the following if the build type is not `beta`:
```javascript
this.store.updateStructure({
...,
GasFeeController: this.gasFeeController,
TokenListController: this.tokenListController,
});
```
Co-authored-by: Mark Stacey <markjstacey@gmail.com>
