code coverage issue in wtr

This repo demonstrates how a HTML test can affect the overall code coverage result.

Setup

# Install dependencies
$ npm i

How to reproduce the issue

Steps to reproduce the issue is as follows:

1. First, run npm t to see the test runner reports 100% code coverage.
2. Then, uncomment L29 in web-test-runner.config.mjs and run npm t.
3. Now, you will see the code coverage drops below 100% even though all LOCs are covered and tested in all tests.

Output

Code coverage with JS tests only

All codes are covered in JS tests and it shows 100% code coverage.

Code coverage with JS and HTML tests

All codes are covered in JS tests but not in HTML test. This causes the code coverage to drop below 100% even though all lines of code are covered in JS tests.