using fixtures for tests in indexes/test_base.py. Introducing unique_nulls_fixture, because otherwise it is just too troublesome to filter out all types of nans

Author: realead

pandas/conftest.py

@@ -278,6 +278,18 @@ def nulls_fixture(request):
 nulls_fixture2 = nulls_fixture  # Generate cartesian product of nulls_fixture
 
 
+@pytest.fixture(params=[None, np.nan, pd.NaT])
+def unique_nulls_fixture(request):
+    """
+    Fixture for each null type in pandas, each null type exactly once
+    """
+    return request.param
+
+
+# Generate cartesian product of unique_nulls_fixture:
+unique_nulls_fixture2 = unique_nulls_fixture
+
+
 TIMEZONES = [None, 'UTC', 'US/Eastern', 'Asia/Tokyo', 'dateutil/US/Pacific',
              'dateutil/Asia/Singapore']
 

pandas/tests/indexes/test_base.py

@@ -1245,19 +1245,20 @@ def test_get_indexer(self):
         e1 = np.array([1, 3, -1], dtype=np.intp)
         assert_almost_equal(r1, e1)
 
-    def test_get_indexer_with_NA_values(self):
+    def test_get_indexer_with_NA_values(self, unique_nulls_fixture,
+                                        unique_nulls_fixture2):
         # GH 22332
         # check pairwise, that no pair of na values
         # is mangled
-        na_values = [None, np.nan, pd.NaT]
-        for f in na_values:
-            for s in na_values:
-                if f is not s:  # otherwise not unique
-                    arr = np.array([f, s], dtype=np.object)
-                    index = pd.Index(arr, dtype=np.object)
-                    result = index.get_indexer([f, s, 'Unknown'])
-                    expected = np.array([0, 1, -1], dtype=np.int64)
-                    tm.assert_numpy_array_equal(result, expected)
+        if unique_nulls_fixture is unique_nulls_fixture2:
+            return  # skip it, values are not unique
+        arr = np.array([unique_nulls_fixture,
+                        unique_nulls_fixture2], dtype=np.object)
+        index = pd.Index(arr, dtype=np.object)
+        result = index.get_indexer([unique_nulls_fixture,
+                                    unique_nulls_fixture2, 'Unknown'])
+        expected = np.array([0, 1, -1], dtype=np.int64)
+        tm.assert_numpy_array_equal(result, expected)
 
     @pytest.mark.parametrize("reverse", [True, False])
     @pytest.mark.parametrize("expected,method", [