I am done

rl/Lib/site-packages/matplotlib/tests/test_basic.py

@@ -0,0 +1,48 @@
+import builtins
+import os
+import sys
+import textwrap
+
+from matplotlib.testing import subprocess_run_for_testing
+
+
+def test_simple():
+    assert 1 + 1 == 2
+
+
+def test_override_builtins():
+    import pylab  # type: ignore
+    ok_to_override = {
+        '__name__',
+        '__doc__',
+        '__package__',
+        '__loader__',
+        '__spec__',
+        'any',
+        'all',
+        'sum',
+        'divmod'
+    }
+    overridden = {key for key in {*dir(pylab)} & {*dir(builtins)}
+                  if getattr(pylab, key) != getattr(builtins, key)}
+    assert overridden <= ok_to_override
+
+
+def test_lazy_imports():
+    source = textwrap.dedent("""
+    import sys
+
+    import matplotlib.figure
+    import matplotlib.backend_bases
+    import matplotlib.pyplot
+
+    assert 'matplotlib._tri' not in sys.modules
+    assert 'matplotlib._qhull' not in sys.modules
+    assert 'matplotlib._contour' not in sys.modules
+    assert 'urllib.request' not in sys.modules
+    """)
+
+    subprocess_run_for_testing(
+        [sys.executable, '-c', source],
+        env={**os.environ, "MPLBACKEND": "", "MATPLOTLIBRC": os.devnull},
+        check=True)