refactor the tests

[amtoine]

cc/ @AucaCoyan

did you know i like refactoring things? 😏

in this PR, i propose

• breaking the multi-line ignore_comments test into multiple lines => this makes the whole structure easier to see imo, e.g. the fact that nufmt adds a trailing whitespace after myfunc(one)

Warning
also we have to keep in mind that nufmt works just fine with invalid nu code, e.g. ignore_comments is not valid nu code 🤔

• renaming nu into input in the tests to test nufmt(input) == expected
• writing a run_test wrapper that calls nufmt and assert the values

[AucaCoyan]

I love it!
I knew a good refactor was coming for these tests.
Much of the code base is ugly today, but the important part is that it works. Slowly but surely we will refactor it beautifully 💯

[amtoine]

I love it!

cool, i take that for an approval then 😊

I knew a good refactor was coming for these tests.

here it comes 💪

Much of the code base is ugly today, but the important part is that it works. Slowly but surely we will refactor it beautifully 100

yup agree 😌