diff --git a/pandas/tests/indexes/datetimes/test_misc.py b/pandas/tests/indexes/datetimes/test_misc.py
index eff87a2b3f275..c3736d588601b 100644
--- a/pandas/tests/indexes/datetimes/test_misc.py
+++ b/pandas/tests/indexes/datetimes/test_misc.py
@@ -366,6 +366,7 @@ def test_datetime_name_accessors(self, time_locale):
         for day, name, eng_name in zip(range(4, 11), expected_days, english_days):
             name = name.capitalize()
             assert dti.day_name(locale=time_locale)[day] == name
+            assert dti.day_name(locale=None)[day] == eng_name
             ts = Timestamp(datetime(2016, 4, day))
             assert ts.day_name(locale=time_locale) == name
         dti = dti.append(DatetimeIndex([pd.NaT]))
diff --git a/pandas/tests/indexes/period/test_indexing.py b/pandas/tests/indexes/period/test_indexing.py
index 9b7685b23289a..e820c2250256e 100644
--- a/pandas/tests/indexes/period/test_indexing.py
+++ b/pandas/tests/indexes/period/test_indexing.py
@@ -589,7 +589,7 @@ def test_where(self, klass):
     def test_where_other(self):
         i = period_range("20130101", periods=5, freq="D")
         for arr in [np.nan, NaT]:
-            result = i.where(notna(i), other=np.nan)
+            result = i.where(notna(i), other=arr)
             expected = i
             tm.assert_index_equal(result, expected)
 
diff --git a/pandas/tests/series/accessors/test_dt_accessor.py b/pandas/tests/series/accessors/test_dt_accessor.py
index 5db159e1abb80..dcdee01bd4df8 100644
--- a/pandas/tests/series/accessors/test_dt_accessor.py
+++ b/pandas/tests/series/accessors/test_dt_accessor.py
@@ -443,6 +443,7 @@ def test_dt_accessor_datetime_name_accessors(self, time_locale):
         for day, name, eng_name in zip(range(4, 11), expected_days, english_days):
             name = name.capitalize()
             assert s.dt.day_name(locale=time_locale)[day] == name
+            assert s.dt.day_name(locale=None)[day] == eng_name
         s = s.append(Series([pd.NaT]))
         assert np.isnan(s.dt.day_name(locale=time_locale).iloc[-1])