[rpms/python-dask] rawhide: Disable one test to enable Python 3.15 rebuild

[Lumir Balhar <lbalhar@redhat.com>]

            A new commit has been pushed.

            Repo   : rpms/python-dask
            Branch : rawhide
            Commit : 9fe8111ed55099089dcead174db45e3a884d1cd0
            Author : Lumir Balhar <lbalhar@redhat.com>
            Date   : 2026-06-16T13:27:40+02:00
            Stats  : +5/-0 in 1 file(s)
            URL    : https://src.fedoraproject.org/rpms/python-dask/c/9fe8111ed55099089dcead174db45e3a884d1cd0?branch=rawhide

            Log:
            Disable one test to enable Python 3.15 rebuild

[skip changelog]

---
diff --git a/python-dask.spec b/python-dask.spec
index cd66eef..fc9e394 100644
--- a/python-dask.spec
+++ b/python-dask.spec
@@ -159,6 +159,11 @@ k="${k-}${k+ and }not test_development_guidelines_matches_ci"
 # restrictive.
 k="${k-}${k+ and }not test_serialization"
 
+# On Python 3.15, calling os.fork() in a multi-threaded process (as pytest-xdist
+# workers are) raises DeprecationWarning as an exception. This test explicitly
+# exercises the fork multiprocessing context and cannot pass in this environment.
+k="${k-}${k+ and }not test_custom_context_used_python3_posix"
+
 # Previously excluded for dask-expr. Those tests use parquet files,
 # which involves pyarrow.
 %ifarch s390x