Fix headless tests on Wayland.

QuLogic · QuLogic · commit 2bfba7c70ae2 · 2020-12-09T15:56:59.000-05:00
Since #17396, backends now check for Wayland settings as part of headless detection. However, the headless tests do not override those settings. When running on Wayland, they thus think the display exists when they are not supposed to.
diff --git a/lib/matplotlib/tests/test_backends_interactive.py b/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 +41,8 @@ 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 = "$DISPLAY is unset"
+        if sys.platform == "linux" and _c_internal_utils.display_is_valid():
+            reason = "$DISPLAY and $WAYLAND_DISPLAY are unset"
         elif missing:
             reason = "{} cannot be imported".format(", ".join(missing))
         elif backend == 'macosx' and os.environ.get('TF_BUILD'):
@@ -277,6 +278,7 @@ def test_lazy_linux_headless():
 
 # make it look headless
 del os.environ['DISPLAY']
+del os.environ['WAYLAND_DISPLAY']
 
 # we should fast-track to Agg
 import matplotlib.pyplot as plt
diff --git a/lib/matplotlib/tests/test_rcparams.py b/lib/matplotlib/tests/test_rcparams.py
@@ -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 +488,10 @@ 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 os.environ.get("DISPLAY") and not os.environ.get("WAYLAND_DISPLAY"),
+    reason="headless")
 def test_backend_fallback_headful(tmpdir):
     pytest.importorskip("tkinter")
     env = {**os.environ, "MPLBACKEND": "", "MPLCONFIGDIR": str(tmpdir)}
