Most Python-based system tests need to know which ports were assigned to
a given test by bin/tests/system/get_ports.sh. This is currently
handled by inspecting the values of various environment variables (set
by bin/tests/system/run.sh) and passing the port numbers to Python
scripts via pytest fixtures. However, this glue code has so far been
copy-pasted into each system test using it, rather than reused.
Since pytest also looks for conftest.py files in parent directories,
move commonly used fixtures to bin/tests/system/conftest.py. Set the
scope of all the moved fixtures to "session" as their return values are
only based on environment variables, so there is no point in recreating
them for every test requesting them. Adjust test code accordingly.
This commit converts the license handling to adhere to the REUSE
specification. It specifically:
1. Adds used licnses to LICENSES/ directory
2. Add "isc" template for adding the copyright boilerplate
3. Changes all source files to include copyright and SPDX license
header, this includes all the C sources, documentation, zone files,
configuration files. There are notes in the doc/dev/copyrights file
on how to add correct headers to the new files.
4. Handle the rest that can't be modified via .reuse/dep5 file. The
binary (or otherwise unmodifiable) files could have license places
next to them in <foo>.license file, but this would lead to cluttered
repository and most of the files handled in the .reuse/dep5 file are
system test files.
The TCP connection reset test starts mock UDP and TCP server which
always returns empty DNS answer with TC bit set over UDP and resets the
TCP connection after five seconds.
When tested without the fix, the DNS query to 10.53.0.2 times out and
the ns2 server hangs at shutdown.
