Cancel the current test when no keystrokes have been typed for X seconds.
You know, that moment when you start a test, interrupt it for some reason, and forget to (or can't) reload it. This results in an abnormally low score, which drastically drops your average. This has happened and still happens to a lot of people for years.
So I suggest setting up a security that would automatically cancel the test when no keystrokes have been detected, let's say for 5 or 10 seconds, for example.
This would put an end to this recurring and demoralizing plague.