Describe the bug
Currently the python testing driver runs this check on each test script

And this is great because it ensures a good code style within the testing scripts.
But unfortunately it isn't as straightforward as this, I can think of couple cases already where this can cause headaches for people

• generated testing scripts/injected

I wrote

• nixpkgs/nixos/tests/installed-tests/default.nix

  Line 25 in 85f3d86

  , preTestScript ? ""

recently and it can error out on the final testing script, but that is already abstracted by this function so it doesn't really matter. I had to make special measure to try to appease black.

• nix store paths/nix values

We used nix to keep line width manageable in this test

• nixpkgs/nixos/tests/gnome3.nix

  Line 28 in 85f3d86

  # Keep line widths somewhat managable

but if I were to port this to python I'd need to format the code like

machine.wait_until_succeeds(
    "su - alice -c '${startingUp} | grep -q true,..false'"
)

because those values get interpolated and then became really long.
Same if you use a nix store path attribute anywhere, it'll likely error out on the line being too long.

Solutions
We need to relax a lot of black's settings.
@adisbladis pasted these, as to what they're using personally:

• http://dpaste.com/1MPTRKR
• http://dpaste.com/2TW6V8N

And for sure relax string literal lengths to be larger, because of the reasons I mentioned.