Backport PR #36706: CI: npdev new exception message (#36751)

Co-authored-by: jbrockmendel <jbrockmendel@gmail.com>

Author: meeseeksmachine

pandas/tests/arithmetic/common.py

@@ -76,6 +76,13 @@ def assert_invalid_comparison(left, right, box):
             "Cannot compare type",
             "not supported between",
             "invalid type promotion",
+            (
+                # GH#36706 npdev 1.20.0 2020-09-28
+                r"The DTypes <class 'numpy.dtype\[datetime64\]'> and "
+                r"<class 'numpy.dtype\[int64\]'> do not have a common DType. "
+                "For example they cannot be stored in a single array unless the "
+                "dtype is `object`."
+            ),
         ]
     )
     with pytest.raises(TypeError, match=msg):

pandas/tests/frame/test_arithmetic.py

@@ -53,6 +53,11 @@ def check(df, df2):
                 msgs = [
                     r"Invalid comparison between dtype=datetime64\[ns\] and ndarray",
                     "invalid type promotion",
+                    (
+                        # npdev 1.20.0
+                        r"The DTypes <class 'numpy.dtype\[.*\]'> and "
+                        r"<class 'numpy.dtype\[.*\]'> do not have a common DType."
+                    ),
                 ]
                 msg = "|".join(msgs)
                 with pytest.raises(TypeError, match=msg):