Add test

Author: Daniel Saxton

Diff for: pandas/tests/arrays/test_boolean.py

@@ -929,3 +929,13 @@ def test_diff():
     result = s.diff()
     expected = pd.Series(expected)
     tm.assert_series_equal(result, expected)
+
+
+def test_nullable_boolean_filter():
+    s = pd.Series([1, 2, 3])
+    mask = pd.array([True, True, None], dtype="boolean")
+
+    result = s[mask]
+    expected = s.iloc[:2]
+
+    tm.assert_series_equal(result, expected)