"no tests have been done" or "no test has been done"?

Question

Should I say "no tests have been done" or "no test has been done" in case when only one test could possibly be done?

For example, in the case of a director who entered an empty classroom where a reportedly lazy teacher works, he may report to the principle as:

I've checked all her papers. The tests on papers 1 through 5 have been done, however, no tests have been done on paper 6 yet

So, here the plural "no tests have been done" is used because there are more than one students in the class.

However, if it's one of those student's parent writing a complaint about that lazy teacher to the principal, then could he/she write something like:

It's been already quite a long time since my daughter's progress has been tested. The tests on papers 1 through 5 were done long time ago. And no test has been done on paper 6 yet

?

Answer 1

It should be “no test has been done” in both cases, because there is only one test per paper. The number of test recipients is irrelevant.

Answer 2

...That's rather unidiomatic, phrasing it like that. Better would probably be "there hasn't been a test" for a test that hasn't occured, or "the test hasn't been graded" for a test that hasn't been marked yet. In all cases, all the versions of the test and every individual test paper are regarded as a singular "test", although sometimes it makes sense to say "I graded your tests" when there was only one test.