Fix another PyYAML / Cython 3 related bitrot.

tests/integration/test_issue_1316.py

@@ -3,6 +3,9 @@
 
 import os
 import subprocess
+import sys
+
+import pytest
 
 from pex.testing import run_pex_command
 from pex.typing import TYPE_CHECKING
@@ -11,8 +14,19 @@
     from typing import Any
 
 
+@pytest.mark.skipif(sys.version_info[:2] < (3, 6), reason="PyYAML 6.0.1 requires Python >= 3.6")
 def test_resolve_cyclic_dependency_graph(tmpdir):
     # type: (Any) -> None
     naked_pex = os.path.join(str(tmpdir), "naked.pex")
-    run_pex_command(args=["Naked==0.1.31", "-o", naked_pex]).assert_success()
+
+    # N.B.: Naked 0.1.31 requires PyYAML unbounded and old versions of PyYAML that work with Python
+    # 2.7 have been broken by the Cython 3.0.0 release. As such we exclude older versions of Python
+    # from this test and pin PyYAML to a newer version that works with Cython>=3.
+    constraints = os.path.join(str(tmpdir), "constraints.txt")
+    with open(constraints, "w") as fp:
+        fp.write("PyYAML==6.0.1")
+
+    run_pex_command(
+        args=["Naked==0.1.31", "--constraints", constraints, "-o", naked_pex]
+    ).assert_success()
     subprocess.check_call(args=[naked_pex, "-c", "import Naked"])