Test fixup

- actually switch the default to not warn
- We do overwrite matplotlib's formatters

Author: TomAugspurger

pandas/plotting/_converter.py

@@ -62,7 +62,7 @@ def get_pairs():
     return pairs
 
 
-def register(explicit=False):
+def register(explicit=True):
     """Register Pandas Formatters and Converters with matplotlib
 
     This function modifies the global ``matplotlib.units.registry``

pandas/tests/plotting/test_converter.py

@@ -109,7 +109,7 @@ def test_registry_resets(self):
             units.registry[date] = date_converter
 
             register_matplotlib_converters()
-            assert units.registry[date] is date_converter
+            assert units.registry[date] is not date_converter
             deregister_matplotlib_converters()
             assert units.registry[date] is date_converter