TST: Old issues

pandas/tests/frame/indexing/test_where.py

@@ -745,3 +745,15 @@ def test_where_bool_comparison():
         }
     )
     tm.assert_frame_equal(result, expected)
+
+
+def test_where_none_nan_coerce():
+    # GH 15613
+    expected = DataFrame(
+        {
+            "A": [Timestamp("20130101"), pd.NaT, Timestamp("20130103")],
+            "B": [1, 2, np.nan],
+        }
+    )
+    result = expected.where(expected.notnull(), None)
+    tm.assert_frame_equal(result, expected)

pandas/tests/frame/methods/test_to_csv.py

@@ -1330,3 +1330,14 @@ def test_to_csv_numpy_16_bug(self):
 
         result = buf.getvalue()
         assert "2000-01-01" in result
+
+    def test_to_csv_na_quoting(self):
+        # GH 15891
+        # Normalize carriage return for Windows OS
+        result = (
+            DataFrame([None, None])
+            .to_csv(None, header=False, index=False, na_rep="")
+            .replace("\r\n", "\n")
+        )
+        expected = '""\n""\n'
+        assert result == expected

pandas/tests/groupby/test_groupby.py

@@ -1657,7 +1657,7 @@ def test_index_label_overlaps_location():
     expected = ser.take([1, 3, 4])
     tm.assert_series_equal(actual, expected)
 
-    # ... and again, with a generic Index of floats
+    #  and again, with a generic Index of floats
     df.index = df.index.astype(float)
     g = df.groupby(list("ababb"))
     actual = g.filter(lambda x: len(x) > 2)
@@ -2283,3 +2283,23 @@ def test_groupby_empty_multi_column():
         [], columns=["C"], index=MultiIndex([[], []], [[], []], names=["A", "B"])
     )
     tm.assert_frame_equal(result, expected)
+
+
+def test_groupby_filtered_df_std():
+    # GH 16174
+    dicts = [
+        {"filter_col": False, "groupby_col": True, "bool_col": True, "float_col": 10.5},
+        {"filter_col": True, "groupby_col": True, "bool_col": True, "float_col": 20.5},
+        {"filter_col": True, "groupby_col": True, "bool_col": True, "float_col": 30.5},
+    ]
+    df = DataFrame(dicts)
+
+    df_filter = df[df["filter_col"] == True]  # noqa:E712
+    dfgb = df_filter.groupby("groupby_col")
+    result = dfgb.std()
+    expected = DataFrame(
+        [[0.0, 0.0, 7.071068]],
+        columns=["filter_col", "bool_col", "float_col"],
+        index=Index([True], name="groupby_col"),
+    )
+    tm.assert_frame_equal(result, expected)

pandas/tests/indexing/multiindex/test_loc.py

@@ -801,3 +801,33 @@ def test_mi_partial_indexing_list_raises():
     frame.columns.names = ["state", "color"]
     with pytest.raises(KeyError, match="\\[2\\] not in index"):
         frame.loc[["b", 2], "Colorado"]
+
+
+def test_mi_indexing_list_nonexistent_raises():
+    # GH 15452
+    s = Series(range(4), index=MultiIndex.from_product([[1, 2], ["a", "b"]]))
+    with pytest.raises(KeyError, match="\\['not' 'found'\\] not in index"):
+        s.loc[["not", "found"]]
+
+
+def test_mi_add_cell_missing_row_non_unique():
+    # GH 16018
+    result = DataFrame(
+        [[1, 2, 5, 6], [3, 4, 7, 8]],
+        index=["a", "a"],
+        columns=MultiIndex.from_product([[1, 2], ["A", "B"]]),
+    )
+    result.loc["c"] = -1
+    result.loc["c", (1, "A")] = 3
+    result.loc["d", (1, "A")] = 3
+    expected = DataFrame(
+        [
+            [1.0, 2.0, 5.0, 6.0],
+            [3.0, 4.0, 7.0, 8.0],
+            [3.0, -1.0, -1, -1],
+            [3.0, np.nan, np.nan, np.nan],
+        ],
+        index=["a", "a", "c", "d"],
+        columns=MultiIndex.from_product([[1, 2], ["A", "B"]]),
+    )
+    tm.assert_frame_equal(result, expected)

pandas/tests/indexing/test_loc.py

@@ -2684,3 +2684,14 @@ def test_loc_assign_dict_to_row(self, dtype):
         expected = DataFrame({"A": ["newA", "def"], "B": ["newB", "jkl"]}, dtype=dtype)
 
         tm.assert_frame_equal(df, expected)
+
+    @td.skip_array_manager_invalid_test
+    def test_loc_setitem_dict_timedelta_multiple_set(self):
+        # GH 16309
+        result = DataFrame(columns=["time", "value"])
+        result.loc[1] = {"time": Timedelta(6, unit="s"), "value": "foo"}
+        result.loc[1] = {"time": Timedelta(6, unit="s"), "value": "foo"}
+        expected = DataFrame(
+            [[Timedelta(6, unit="s"), "foo"]], columns=["time", "value"], index=[1]
+        )
+        tm.assert_frame_equal(result, expected)

pandas/tests/scalar/timestamp/test_constructors.py

@@ -437,6 +437,13 @@ def test_bounds_with_different_units(self):
                 dt64 = np.datetime64(date_string, unit)
                 Timestamp(dt64)
 
+    @pytest.mark.parametrize("arg", ["001-01-01", "0001-01-01"])
+    def test_out_of_bounds_string_consistency(self, arg):
+        # GH 15829
+        msg = "Out of bounds"
+        with pytest.raises(OutOfBoundsDatetime, match=msg):
+            Timestamp(arg)
+
     def test_min_valid(self):
         # Ensure that Timestamp.min is a valid Timestamp
         Timestamp(Timestamp.min)

pandas/tests/tools/test_to_numeric.py

@@ -780,3 +780,10 @@ def test_downcast_nullable_mask_is_copied():
 
     arr[1] = pd.NA  # should not modify result
     tm.assert_extension_array_equal(result, expected)
+
+
+def test_to_numeric_scientific_notation():
+    # GH 15898
+    result = to_numeric("1.7e+308")
+    expected = np.float64(1.7e308)
+    assert result == expected