Fix tests and warning message

Author: ryankarlos

pandas/__init__.py

@@ -212,9 +212,9 @@ class Panel:
 
         elif name == "datetime":
             warnings.warn(
-                "The datetime class is removed from pandas. Accessing it from "
-                "the top-level namespace will also be removed in the next "
-                "version",
+                "The pandas.datetime module is deprecated "
+                "and will be removed from pandas in a future version. "
+                "Import datetime directly instead.",
                 FutureWarning,
                 stacklevel=2,
             )
@@ -257,9 +257,9 @@ def __init__(self):
 
         def __getattr__(self, item):
             self.warnings.warn(
-                "The pandas.datetime module is deprecated and will be "
-                "removed from pandas in a future version. Import numpy "
-                "directly instead",
+                "The pandas.datetime module is deprecated "
+                "and will be removed from pandas in a future version. "
+                "Import datetime directly instead.",
                 FutureWarning,
                 stacklevel=2,
             )

pandas/tests/api/test_api.py

@@ -224,10 +224,13 @@ def test_api(self):
 
 def test_datetime():
     from datetime import datetime
-    import warnings
+    import pytest
 
-    with warnings.catch_warnings():
-        warnings.simplefilter("ignore", FutureWarning)
+    msg = "The pandas.datetime module is deprecated " \
+          "and will be removed from pandas in a future version. " \
+          "Import datetime directly instead."
+
+    with pytest.warns(FutureWarning, match=msg):
         assert datetime(2015, 1, 2, 0, 0) == pd.datetime(2015, 1, 2, 0, 0)