TST/REF: SetitemCastingEquivalents (#39477)

Author: jbrockmendel

pandas/tests/series/indexing/test_setitem.py

@@ -282,56 +282,9 @@ def test_setitem_dt64_into_int_series(self, dtype):
         tm.assert_series_equal(ser, expected)
 
 
-@pytest.mark.parametrize(
-    "obj,expected,key",
-    [
-        pytest.param(
-            # these induce dtype changes
-            Series([2, 3, 4, 5, 6, 7, 8, 9, 10]),
-            Series([np.nan, 3, np.nan, 5, np.nan, 7, np.nan, 9, np.nan]),
-            slice(None, None, 2),
-            id="int_series_slice_key_step",
-        ),
-        pytest.param(
-            Series([True, True, False, False]),
-            Series([np.nan, True, np.nan, False], dtype=object),
-            slice(None, None, 2),
-            id="bool_series_slice_key_step",
-        ),
-        pytest.param(
-            # these induce dtype changes
-            Series(np.arange(10)),
-            Series([np.nan, np.nan, np.nan, np.nan, np.nan, 5, 6, 7, 8, 9]),
-            slice(None, 5),
-            id="int_series_slice_key",
-        ),
-        pytest.param(
-            # changes dtype GH#4463
-            Series([1, 2, 3]),
-            Series([np.nan, 2, 3]),
-            0,
-            id="int_series_int_key",
-        ),
-        pytest.param(
-            # changes dtype GH#4463
-            Series([False]),
-            Series([np.nan], dtype=object),
-            # TODO: maybe go to float64 since we are changing the _whole_ Series?
-            0,
-            id="bool_series_int_key_change_all",
-        ),
-        pytest.param(
-            # changes dtype GH#4463
-            Series([False, True]),
-            Series([np.nan, True], dtype=object),
-            0,
-            id="bool_series_int_key",
-        ),
-    ],
-)
-class TestSetitemCastingEquivalents:
+class SetitemCastingEquivalents:
     """
-    Check each of several methods that _should_ be equivalent to `obj[key] = np.nan`
+    Check each of several methods that _should_ be equivalent to `obj[key] = val`
 
     We assume that
         - obj.index is the default Index(range(len(obj)))
@@ -346,26 +299,44 @@ def val(self, request):
         """
         return request.param
 
+    def check_indexer(self, obj, key, expected, val, indexer):
+        obj = obj.copy()
+        indexer(obj)[key] = val
+        tm.assert_series_equal(obj, expected)
+
     def test_int_key(self, obj, key, expected, val, indexer_sli):
         if not isinstance(key, int):
             return
 
-        obj = obj.copy()
-        indexer_sli(obj)[key] = val
-        tm.assert_series_equal(obj, expected)
+        self.check_indexer(obj, key, expected, val, indexer_sli)
 
-    def test_slice_key(self, obj, key, expected, val, indexer_si):
-        # Note: no .loc because that handles slice edges differently
-        obj = obj.copy()
-        indexer_si(obj)[key] = val
-        tm.assert_series_equal(obj, expected)
+        rng = range(key, key + 1)
+        self.check_indexer(obj, rng, expected, val, indexer_sli)
+
+        if indexer_sli is not tm.loc:
+            # Note: no .loc because that handles slice edges differently
+            slc = slice(key, key + 1)
+            self.check_indexer(obj, slc, expected, val, indexer_sli)
+
+        ilkey = [key]
+        self.check_indexer(obj, ilkey, expected, val, indexer_sli)
+
+        indkey = np.array(ilkey)
+        self.check_indexer(obj, indkey, expected, val, indexer_sli)
+
+    def test_slice_key(self, obj, key, expected, val, indexer_sli):
+        if not isinstance(key, slice):
+            return
+
+        if indexer_sli is not tm.loc:
+            # Note: no .loc because that handles slice edges differently
+            self.check_indexer(obj, key, expected, val, indexer_sli)
 
-    def test_intlist_key(self, obj, key, expected, val, indexer_sli):
         ilkey = list(range(len(obj)))[key]
+        self.check_indexer(obj, ilkey, expected, val, indexer_sli)
 
-        obj = obj.copy()
-        indexer_sli(obj)[ilkey] = val
-        tm.assert_series_equal(obj, expected)
+        indkey = np.array(ilkey)
+        self.check_indexer(obj, indkey, expected, val, indexer_sli)
 
     def test_mask_key(self, obj, key, expected, val, indexer_sli):
         # setitem with boolean mask
@@ -412,6 +383,63 @@ def test_index_putmask(self, obj, key, expected, val):
         tm.assert_index_equal(res, Index(expected))
 
 
+@pytest.mark.parametrize(
+    "obj,expected,key",
+    [
+        pytest.param(
+            # these induce dtype changes
+            Series([2, 3, 4, 5, 6, 7, 8, 9, 10]),
+            Series([np.nan, 3, np.nan, 5, np.nan, 7, np.nan, 9, np.nan]),
+            slice(None, None, 2),
+            id="int_series_slice_key_step",
+        ),
+        pytest.param(
+            Series([True, True, False, False]),
+            Series([np.nan, True, np.nan, False], dtype=object),
+            slice(None, None, 2),
+            id="bool_series_slice_key_step",
+        ),
+        pytest.param(
+            # these induce dtype changes
+            Series(np.arange(10)),
+            Series([np.nan, np.nan, np.nan, np.nan, np.nan, 5, 6, 7, 8, 9]),
+            slice(None, 5),
+            id="int_series_slice_key",
+        ),
+        pytest.param(
+            # changes dtype GH#4463
+            Series([1, 2, 3]),
+            Series([np.nan, 2, 3]),
+            0,
+            id="int_series_int_key",
+        ),
+        pytest.param(
+            # changes dtype GH#4463
+            Series([False]),
+            Series([np.nan], dtype=object),
+            # TODO: maybe go to float64 since we are changing the _whole_ Series?
+            0,
+            id="bool_series_int_key_change_all",
+        ),
+        pytest.param(
+            # changes dtype GH#4463
+            Series([False, True]),
+            Series([np.nan, True], dtype=object),
+            0,
+            id="bool_series_int_key",
+        ),
+    ],
+)
+class TestSetitemCastingEquivalents(SetitemCastingEquivalents):
+    @pytest.fixture(params=[np.nan, np.float64("NaN")])
+    def val(self, request):
+        """
+        One python float NaN, one np.float64.  Only np.float64 has a `dtype`
+        attribute.
+        """
+        return request.param
+
+
 class TestSetitemWithExpansion:
     def test_setitem_empty_series(self):
         # GH#10193