Merge pull request matplotlib#19083 from QuLogic/headless-tests

Fix headless tests on Wayland.

Author: tacaswell

lib/matplotlib/tests/test_backends_interactive.py

@@ -12,6 +12,7 @@
 import pytest
 
 import matplotlib as mpl
+from matplotlib import _c_internal_utils
 
 
 # Minimal smoke-testing of the backends for which the dependencies are
@@ -40,8 +41,9 @@ def _get_testable_interactive_backends():
     ]:
         reason = None
         missing = [dep for dep in deps if not importlib.util.find_spec(dep)]
-        if sys.platform == "linux" and not os.environ.get("DISPLAY"):
-            reason = "$DISPLAY is unset"
+        if (sys.platform == "linux" and
+                not _c_internal_utils.display_is_valid()):
+            reason = "$DISPLAY and $WAYLAND_DISPLAY are unset"
         elif missing:
             reason = "{} cannot be imported".format(", ".join(missing))
         elif backend == 'macosx' and os.environ.get('TF_BUILD'):
@@ -276,7 +278,8 @@ def test_lazy_linux_headless():
 import sys
 
 # make it look headless
-del os.environ['DISPLAY']
+os.environ.pop('DISPLAY', None)
+os.environ.pop('WAYLAND_DISPLAY', None)
 
 # we should fast-track to Agg
 import matplotlib.pyplot as plt

lib/matplotlib/tests/test_rcparams.py

@@ -10,7 +10,7 @@
 import pytest
 
 import matplotlib as mpl
-from matplotlib import _api
+from matplotlib import _api, _c_internal_utils
 import matplotlib.pyplot as plt
 import matplotlib.colors as mcolors
 import numpy as np
@@ -476,7 +476,8 @@ def test_rcparams_reset_after_fail():
 @pytest.mark.skipif(sys.platform != "linux", reason="Linux only")
 def test_backend_fallback_headless(tmpdir):
     env = {**os.environ,
-           "DISPLAY": "", "MPLBACKEND": "", "MPLCONFIGDIR": str(tmpdir)}
+           "DISPLAY": "", "WAYLAND_DISPLAY": "",
+           "MPLBACKEND": "", "MPLCONFIGDIR": str(tmpdir)}
     with pytest.raises(subprocess.CalledProcessError):
         subprocess.run(
             [sys.executable, "-c",
@@ -487,8 +488,9 @@ def test_backend_fallback_headless(tmpdir):
             env=env, check=True)
 
 
-@pytest.mark.skipif(sys.platform == "linux" and not os.environ.get("DISPLAY"),
-                    reason="headless")
+@pytest.mark.skipif(
+    sys.platform == "linux" and not _c_internal_utils.display_is_valid(),
+    reason="headless")
 def test_backend_fallback_headful(tmpdir):
     pytest.importorskip("tkinter")
     env = {**os.environ, "MPLBACKEND": "", "MPLCONFIGDIR": str(tmpdir)}