Issue/10991 Make unit tests pass on windows

[nickvergessen]

Further fixing to get #10991 done

Common Problems

uniqid() is not unique on Windows:

If you need a random string in your test please extend the \Test\TestCase class instead of \PHPUnit_Framework_TestCase (Once this PR is merged) and use $this->getUniqueID() instead.

Unclosed handles cause unlink() to fail:

On Windows php can not delete files which still have an open handle. Be sure to fclose() any handles you open, especially before deleting the file or directory.

chmod() does not work on Windows:

Windows does not have read/write permissions like UNIX. If you set chmod to 000 you can still write to the file/directory on Windows. In case you need to test something like that, Please mark the test as skipped for Windows, by adding the following code, right before the first assertion relying on the chmod change. We can still make all other assertions that happen till the change, so add it as late as possible:

    if (\OC_Util::runningOnWindows()) {
        $this->markTestSkipped('[Windows] chmod() does not work as intended on Windows.');
    }

[nickvergessen]

@th3fallen @DeepDiver1975

@MorrisJobke @PVince81 should also fix the encryption tests on unix

[nickvergessen]

@karlitschek while this PR looks quite huge, only 3 files apart from tests have been modified:

• Added fclose() on handle before deleting a file: +1 line
  https://github.com/owncloud/core/pull/12218/files#diff-1
• Added closedir() on handle before returning: +1 line
  https://github.com/owncloud/core/pull/12218/files#diff-15
• Modified normalizePath() to work with absolute paths on windows: +11 lines - 2 lines
  https://github.com/owncloud/core/pull/12218/files#diff-14

Would be nice if we can backport this to stable7 so tests can be run there much better (removes about 100 failures)

[karlitschek]

O.K. please backport. Usually we don´t bckport tests but only important bugfixes. But let´s do this this time if you want.

[PVince81]

Backporting tests is usually a good idea if it doesn't affect the functionality itself. This can help adding another layer of protection against regressions when backporting other stuff.

[PVince81]

Code looks good, unit tests run fine on Linux 👍

[ghost]

🚀 Test PASSed. 🚀
Refer to this link for build results (access rights to CI server needed):
https://ci.owncloud.org//job/pull-request-analyser-ng-simple/2689/
🚀 Test PASSed. 🚀

[MorrisJobke]

Tests run fine. I now will have a look at the code and then will merge this :)

[nickvergessen]

I will make a new PR for the backport, so this gets tested on jenkins correctly against stable7

[MorrisJobke]

Code looks good 👍