Merge pull request matplotlib#30581 from QuLogic/make-test-safer

TST: Force Agg backend in test_openin_any_paranoid

Author: tacaswell

lib/matplotlib/tests/test_texmanager.py

@@ -70,6 +70,7 @@ def test_openin_any_paranoid():
          'import matplotlib.pyplot as plt;'
          'plt.rcParams.update({"text.usetex": True});'
          'plt.title("paranoid");'
-         'plt.show(block=False);'],
-        env={**os.environ, 'openin_any': 'p'}, check=True, capture_output=True)
+         'plt.gcf().canvas.draw();'],
+        env={**os.environ, 'MPLBACKEND': 'Agg', 'openin_any': 'p'},
+        check=True, capture_output=True)
     assert completed.stderr == ""