Merge pull request #20886 from meeseeksmachine/auto-backport-of-pr-20884-on-v3.5.x

tacaswell · web-flow · commit eb38299aa51f · 2021-08-24T13:25:28.000-04:00
Backport PR #20884 on branch v3.5.x (Ensure full environment is passed to headless test.)
diff --git a/lib/matplotlib/tests/test_backends_interactive.py b/lib/matplotlib/tests/test_backends_interactive.py
@@ -301,7 +301,7 @@ def test_lazy_linux_headless():
 
 """
     proc = subprocess.run([sys.executable, "-c", test_script],
-                          env={"MPLBACKEND": ""})
+                          env={**os.environ, "MPLBACKEND": ""})
     if proc.returncode:
         pytest.fail("The subprocess returned with non-zero exit status "
                     f"{proc.returncode}.")
