Fix @covers annotation

[paul-m]

Fixes [issue#]

Describe your changes

This cleans up our CI workflow, where we have seen difficulty with the 'uploading test results' phase.

This was because we had some code coverage annotation in need of fixing, which was adding 'warning' elements to the PHPUnit JUnit report, which in turn caused CircleCI to behave strangely.

TODO: Figure out why CircleCI can't process warning results.

QA Steps

• Visit CircleCI from the CI run here and verify that it does not exhibit errors.

[rovcase]

All eight Circle CI jobs not reporting any errors (in particular on the Uploading test results section), LGTM. Thanks!