TemporaryFolder default name generation inconsistent

TemporaryFolder relies on java.io.File$TempDirectory.

The generateFile method uses SecureRandom to generate a long to ascribe to the file name.

This can cause varying lengths of temporary folder name.

filePath: /tmp/junit2375994787548427572/test.txt --> long is 19 chars filePath: /tmp/junit3617134405501405307/test.txt --> long is 19 chars again filePath: /tmp/junit343221902873074958/test.txt --> long is 18 chars

This was discovered during serialisation of path names and byte length checks in tests causing intermittent issues.

A switch to using a UUID.randomUuid() and actually implementing temp folder creation in junit might be a way to fix this (I don’t see an api on java.io.File which allows passing the random part of the filename).

junit: 4.12 os: ubuntu 20.04

[marcphilipp]

I also don’t see this as a compelling reason to revisit that decision.

[kcooney]

TemporaryFolder used to have its own implementation for creating the directory. We intentionally moved away from that in the recent release of JUnit. I’m not sure this is a compelling reason to revisit that decision.