It's a first step to add code coverage.
In order to get the code coverage report locally, you can run the following command:
```bash
npx gulp unittestcli --coverage
```
The code coverage report will be generated in the `./build/coverage` directory.
And the report can be consulted by opening:
http://localhost:8888/build/coverage/index.html
A GitHub workflow has also been added to run the unit tests with code coverage
on each push and pull request. The report will be uploaded to Codecov.
