I did not even know / remember we had an HTML report, thanks for making me aware, something I'll be using soon for sure.

This PR is missing some minor things:

1. Code style
2. The failing test should not be part of our test suite, it's not actually testing the HTML reporter
3. There should be a test testing the HTML reporter, it should be interacting with the pulblic functions of the reporter directly and confirming the final output.

Since we're currently not testing the HTMLReporter class I can't really put it all on you to fully test the class.
What I'd like you to test are the following functions:

• testUseless
• testError

You'll need to do something like this:

$reportHandle = tmpfile();
$output = ...
$reporter = new HtmlReporter(['html' => stream_get_meta_data($reportHandle)['uri']], $output);
// Test
$reporter->testUseless(...);


// Assert output
rewind($reportHandle);
$report = stream_get_contents($reportHandle);

// Assert that I see some pretty HTML error stuff.

Thanks for the review, I'll get on it soon!