Collect datetime64 and PeriodDtype arithmetic tests (#22237)

Author: jbrockmendel

pandas/tests/arithmetic/__init__.py

@@ -0,0 +1,39 @@
+# -*- coding: utf-8 -*-
+import pytest
+
+import numpy as np
+import pandas as pd
+
+
+@pytest.fixture(params=[1, np.array(1, dtype=np.int64)])
+def one(request):
+    # zero-dim integer array behaves like an integer
+    return request.param
+
+
+# ------------------------------------------------------------------
+
+@pytest.fixture(params=[pd.Index, pd.Series, pd.DataFrame],
+                ids=lambda x: x.__name__)
+def box(request):
+    """
+    Several array-like containers that should have effectively identical
+    behavior with respect to arithmetic operations.
+    """
+    return request.param
+
+
+@pytest.fixture(params=[
+    pd.Index,
+    pd.Series,
+    pytest.param(pd.DataFrame,
+                 marks=pytest.mark.xfail(reason="Tries to broadcast "
+                                                "incorrectly",
+                                         strict=True, raises=ValueError))
+], ids=lambda x: x.__name__)
+def box_df_broadcast_failure(request):
+    """
+    Fixture equivalent to `box` but with the common failing case where
+    the DataFrame operation tries to broadcast incorrectly.
+    """
+    return request.param