[bugfix] Fix TypeError crash in the performance checking phase when the extracted performance variable value is not a number

[victorusu]

Instead of failing when comparing reference of different types with

TypeError: '>=' not supported between instances of 'str' and 'float'

now, ReFrame fails with a much nicer message like (edited by @vkarak)

the value extracted for performance variable 'generic:login:filename' is not a number: 9.c

Closes #1146

[pep8speaks]

Hello @victorusu, Thank you for updating!

• In the file reframe/core/pipeline.py:

Line 1325:36: E127 continuation line over-indented for visual indent
Line 1325:51: E231 missing whitespace after ':'
Line 1325:80: E501 line too long (92 > 79 characters)
Line 1326:80: E501 line too long (90 > 79 characters)
Line 1328:80: E501 line too long (89 > 79 characters)

Do see the ReFrame Coding Style Guide

Comment last updated at 2020-02-24 14:36:00 UTC

[vkarak]

Apart from my other comments, we will need also a unit test to test this.

[vkarak]

@victorusu I have changed the implementation. I am quoting the comment of my last commit:

    Move checking of the perf var extracted variable inside the pipeline

    The reason for that is that we don't do any argument type checking in any other
    sanity function, so it would be strange to do it in either `assert_reference()`
    or `assert_bounded()` only. The reason for that is that type and value errors
    are handled specially if they are raised from user test context. In this
    particular case, though, the `assert_reference()` is called from the framework
    context as a result of user input. So it makes more sense then to do the type
    checking inside `check_performance()`, where we call it.

    We also don't type check the reference and lower/upper thresholds, because this
    should be addressed correctly by the updated declaration of the `reference`
    field as soon as https://github.com/eth-cscs/reframe/issues/1147 is fixed (see
    also related FIXME note for the `reference` field).

    Finally, this commit adds also a pipeline unit test to check for this condition.

[vkarak]

@teojgo Can you review this PR?

I changed completely the implementation, so I need another reviewer