This PR fixes our local unit test package scripts. When the state migration unit tests were migrated to Jest in #12106, it left the `test:unit` script in a broken state, because it didn't tell `mocha` to ignore the state migration tests.
Arguably, that script was already broken, since the most reasonably expectation from its name is that it runs _all_ unit tests. The PR makes it so that it does just that, by means of `concurrently`.
Unfortunately, `concurrently` only outputs errors from child processes once (at the time when they exit, https://github.com/open-cli-tools/concurrently/issues/134). This means that we have to search/navigate the output for this combined script to identify the failure. That said, it's better than the status quo.
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>
Erik Marks