Currently, every unit test that needs a temporary directory creates a directory directly under the system tmp path, /tmp/0df0-cbb9-e3f5-5753 and such. This gets cluttered really quickly, especially if tests fail to clean up. If a directory is left behind it can be tricky to find out which test is the culprit.

I would prefer creating one temporary directory at start of the entire framework, then creating directories under this with the name of the test and optional iteration number. E.g. /tmp/0df0-cbb9-e3f5-5753/dbwrapper_1. This makes it clear if tests leave behind junk, and facilitates cleanup.

Two different mechanisms are used currently for generating temporary directories:

• pathTemp = fs::temp_directory_path() / strprintf("test_bitcoin_%lu_%i", (unsigned long)GetTime(), (int)(InsecureRandRange(100000))) ()
• fs::temp_directory_path() / fs::unique_path()

This would also be unified, then.