Inconsistent Test Execution on Different Workers

Short summary: automation tests split into two groups, one needing a precondition fixture based on worker nodes. During Jenkins runs, test groups execute on different workers each time, causing inconsistency

Description:
Hello all!

I have a next issue and cannot fix it for a while.
So, we have a UI automation repo, with 200 tests. All this test are separated in 2 big groups using pytest.mark.xdist_group
For one group, lets say G1 is required to execute one precondition fixture, and for G2 we dont need this fixture.
And we have next implementation in the code like:
if node == "gw1":
yield
else:
required precondition
And the issue is, every time during jenkins job execution, ours test group executing in diff workers.
Like today G1 tests will run on gw0, and tomorrow G1 tests will run on gw1

Do you know how to fix this ?

Start with the reported pytest.mark.xdist_group and worker-node fixture behavior, then reproduce the differing gw0/gw1 assignments in a Jenkins run. Inspect how pytest-xdist exposes worker identity and how the precondition fixture is selected; done means establishing a consistent, documented way for the two test groups to receive the intended fixture behavior.