Harden the tests for the basics concept exercise

[glennj]

• Test for the expected number of lines
• For task 4, in the passwd file put an unexpected line before the last expected line.

Resolves #337

[github-actions]

This PR touches files which potentially affect the outcome of the tests of an exercise. This will cause all students' solutions to affected exercises to be re-tested.

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[glennj]

There are 200 students who started this exercise, and only 115 have completed it.

I wonder if it's typical that the first concept exercise has such a low completion, or is awk just that weird for people.

• that is even lower than jq, which is that weird.

[rabestro]

There are 200 students who started this exercise, and only 115 have completed it.

I wonder if it's typical that the first concept exercise has such a low completion, or is awk just that weird for people.

• that is even lower than jq, which is that weird.

Is it possible to check student's submissions?
To be able figure out the case for such low percent?

[glennj]

Is it possible to check student's submissions? To be able figure out the case for such low percent?

Jeremy can extract them from the db. But he won't be responsive to such a request for some time.