Bring out a test base for scaling tests - #1277

@IlyaPechersky File with tests become too long, please create one file in addition
you can use this command locally to check if all is good

mvn -B install -Pqulice

@IlyaPechersky actually, #1264 was about something else: we want Qulice to ignore binary files (like PNG, JPEG, or PDF) and don't complain about them. However, your pull request is also interesting, I think we should make it good and then merge.

@yegor256 I realized, it turns out I was really solving another problem)
Now I have separated the common methods and the matcher class into a package so as not to duplicate them in the test classes.
Thus, there are now two types of tests: one checks the content of files, the other meta information.

@pnatashap please, help us review this

@pnatashap do you have any other issues?

@yegor256, Are there any more issues?

@pnatashap can you please take a look one more time?

In this request, two problems were solved at once: making a test base and adding tests for content in files, so for now I have left the solution to only one problem - making a test base

@yegor256 I left only one problem

Is there something else to add?

@yegor256 Thanks for the article! Replaced inheritance with a utility class

@IlyaPechersky utility classes are also a bad idea in OOP: https://www.yegor256.com/2014/05/05/oop-alternative-to-utility-classes.html

We are closing this pull request, because it has merge conflicts with master and has been open for more than a month. Please, forgive us for this: it says nothing about the quality of your work, it's just housekeeping.

If the change still matters to you, please submit a new pull request. It may be very similar to this one, but it has to take into account everything that landed in master since then.

Thank you for contributing, and sorry again for the inconvenience!