tests: Allow running tests from /tmp directory

[maruixin-kls]

This PR fixes issue #781.

Previously, the test helper script (tests/test-utils.sh) restricted the source directory to specific paths (like /home or /usr), causing tests to fail when the source tree was located in /tmp.

This change updates the path validation logic to explicitly allow /tmp, enabling developers to run the test suite from temporary directories.

Fixes: #781

[smcv]

No, this is not a solution. As the doc-comment of BwrapSandbox says, several test-cases assume that /tmp is an empty tmpfs under our control, and therefore that they can safely create predictable, hard-coded paths like /tmp/f in that tmpfs. That won't be true if /tmp is a copy of the "real" /tmp.

Perhaps you could change the BASE_BWRAP_ARGS to put a tmpfs on /dev/shm , then change all the hard-coded uses of /tmp in test-helper.py to be /dev/shm? And then it would be possible to remove the --tmpfs /tmp.

Alternatively, you could do your build in /var/tmp or some other filesystem.