TST: add tests for inplace ops

pandas/tests/series/methods/test_inplace_ops.py

@@ -0,0 +1,60 @@
+import pytest
+
+from pandas import Series
+import pandas._testing as tm
+
+
+@pytest.mark.parametrize(
+    "ser1, ser2, expected_add, expected_sub, expected_mul",
+    (
+        [
+            Series([1], dtype="Int64"),
+            Series([2], dtype="Int64"),
+            Series([3], dtype="Int64"),
+            Series([-1], dtype="Int64"),
+            Series([2], dtype="Int64"),
+        ],
+        [
+            Series([1], dtype="float"),
+            Series([2.0], dtype="float"),
+            Series([3.0], dtype="float"),
+            Series([-1.0], dtype="float"),
+            Series([2.0], dtype="float"),
+        ],
+        [
+            Series([1], dtype="Int64"),
+            Series([2.0], dtype="float"),
+            Series([3.0], dtype="float"),
+            Series([-1.0], dtype="float"),
+            Series([2], dtype="float"),
+        ],
+        [
+            Series([1.0], dtype="float"),
+            Series([2], dtype="Int64"),
+            Series([3.0], dtype="float"),
+            Series([-1.0], dtype="float"),
+            Series([2], dtype="float"),
+        ],
+        pytest.param(
+            Series([1], dtype="Int64"),
+            Series([2.0], dtype="Float64"),
+            Series([3.0], dtype="Float64"),
+            Series([-1.0], dtype="Float64"),
+            Series([2], dtype="Float64"),
+            marks=pytest.mark.xfail(reason="Not implemented yet"),
+        ),
+    ),
+)
+def test_series_inplace_ops(ser1, ser2, expected_add, expected_sub, expected_mul):
+
+    res = ser1.copy()
+    res += ser2
+    tm.assert_series_equal(res, expected_add)
+
+    res = ser1.copy()
+    res -= ser2
+    tm.assert_series_equal(res, expected_sub)
+
+    res = ser1.copy()
+    res *= ser2
+    tm.assert_series_equal(res, expected_mul)