Update gromacs values

[teojgo]

Fixes https://github.com/eth-cscs/reframe-tests/issues/24

[vkarak]

It's a good opportunity to switch this test to the new syntax as well.

[teojgo]

@jenkins-cscs retry all

[vkarak]

Passing arguments to the base constructor is not so new-stylish, and I don't know if it's gonna be supported in the future. The arguments are there just for backward compatibility. The correct way to do it is to set the name and the description afterwards, like that:

class GromacsBaseCheck(rfm.RunOnlyRegressionTest):
    def __init__(self, name, output_file):
        super().__init__()
        self.name = name
        self.descr = 'my gromacs test'

If you set the test's name this way, it is important to set the description also, cos it will hold the automatically generated name otherwise.

[vkarak]

Instead of using tuples, it's perhaps more compact to use one-element lists:

@rfm.parameterized_test([[1], [2], [4], [6], [8]])

Perhaps, I could also update the documentation to show the example with lists instead of tuples.

[vkarak]

In #294, I have changed the decorator to accept multiple arguments, so that you can write this nicer as follows:

@rfm.parameterized_test([1], [2], [4], [6], [8])

You can even use a range as follows:

@rfm.parameterized_test([1], *([x] for x in range(2,9,2)))

[vkarak]

#294 is merged, so you can now use the syntax without the extra brackets.

[vkarak]

You could simply write "node(s)" and avoid this extra complication here.

[vkarak]

Also, I find the original argument name (num_nodes) more accurate than the variant.