The commands executed by pytest during a system test need to have the
same environment variables set as if they were executed by the run.sh
shell script.
It was decided that for the moment, legacy way of executing system tests
with run.sh should be kept, which complicates things a bit. In order to
avoid duplicating the required variables in both conf.sh and pytest, it
was decided to use the existing conf.sh as the only authoritative
place for the variables.
It is necessary to process the environment variables from conf.sh right
when conftest.py is loaded, since they might be needed right away (e.g.
to test for feature support during test collection).
This solution is a bit hacky and is only meant to be used during the
transitory phase when both pytest and the legacy run.sh are both
supported. In the future, a superior pytest-only solution should be
used.
For discussion of other options, refer to
https://gitlab.isc.org/isc-projects/bind9/-/merge_requests/6809#note_318889
The legacy system test framework uses pytest to execute some tests.
Since it'd be quite difficult to convince pytest to decide whether to
include conftest.py (or which ones to include when launching from
subdir), it makes more sense to have a shared conftest.py which is used
by both the legacy test runner invocations of pytest and the new pytest
system test runner. It is ugly, but once we drop support for the legacy
runner, we'll get rid of it.
Properly scope the *port fixtures in order to ensure they'll work as
expected with the new pytest runner. Instead of using "session" (which
means the fixture is only evaluated once for the entire execution of
pytest), use "module" scope, which is evaluated separately for each
module. The legacy runner invoked pytest for each system test
separately, while the new pytest runner is invoked once for all system
tests -- therefore it requires the more fine-grained "module" scope to
for the fixtures to work properly.
Remove python shebang, as conftest.py isn't supposed to be an executable
script.
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.
