Use different directories for cluster marker tests

[tillrohrmann]

Multiple NamedTempFiles are created in the same directory. Therefore,
it happens that the cluster marker test can interfere with each other.
This commit separates the cluster marker tests by creating a temporary
directory in which the cluster marker file gets created.

This fixes #1626.

[AhmedSoliman]

Just checking, is it intentional to "leak" those temporary files after every test?

[tillrohrmann]

Just checking, is it intentional to "leak" those temporary files after every test?

No, it is not. Now with tempdir() they should get removed after the test.

[tillrohrmann]

Sorry for missing the point of into_path() not deleting the directory automatically. I've updated the PR accordingly. Now it should do things as intended, hopefully.

[tillrohrmann]

The PR now seems to pass and should not leave temporary files around. Merging it.

[AhmedSoliman]

We can try that. I'm still not sure I understand how does it fix the actual root cause though.

[tillrohrmann]

We can try that. I'm still not sure I understand how does it fix the actual root cause though.

The problem was that we only created a temporary file for the cluster marker and not a temporary directory. The temporary files were all located in the same directory. When writing the new cluster marker, the process is that we first create the temporary cluster marker in the parent directory and then rename it. Since the temporary cluster marker has a fixed name, the different tests can interfere with each other since they share the same parent directory.