remove now unnecessary warnings

Author: MarcoGorelli

pandas/tests/tools/test_to_datetime.py

@@ -1098,42 +1098,35 @@ def test_convert_object_to_datetime_with_cache(
 
     @pytest.mark.parametrize("cache", [True, False])
     @pytest.mark.parametrize(
-        ("input", "expected", "warning"),
+        ("input", "expected"),
         (
             (
                 Series([NaT] * 20 + [None] * 20, dtype="object"),
                 Series([NaT] * 40, dtype="datetime64[ns]"),
-                None,
             ),
             (
                 Series([NaT] * 60 + [None] * 60, dtype="object"),
                 Series([NaT] * 120, dtype="datetime64[ns]"),
-                None,
             ),
-            (Series([None] * 20), Series([NaT] * 20, dtype="datetime64[ns]"), None),
-            (Series([None] * 60), Series([NaT] * 60, dtype="datetime64[ns]"), None),
+            (Series([None] * 20), Series([NaT] * 20, dtype="datetime64[ns]")),
+            (Series([None] * 60), Series([NaT] * 60, dtype="datetime64[ns]")),
             (
                 Series([""] * 20),
                 Series([NaT] * 20, dtype="datetime64[ns]"),
-                UserWarning,
             ),
             (
                 Series([""] * 60),
                 Series([NaT] * 60, dtype="datetime64[ns]"),
-                UserWarning,
             ),
-            (Series([pd.NA] * 20), Series([NaT] * 20, dtype="datetime64[ns]"), None),
-            (Series([pd.NA] * 60), Series([NaT] * 60, dtype="datetime64[ns]"), None),
-            (Series([np.NaN] * 20), Series([NaT] * 20, dtype="datetime64[ns]"), None),
-            (Series([np.NaN] * 60), Series([NaT] * 60, dtype="datetime64[ns]"), None),
+            (Series([pd.NA] * 20), Series([NaT] * 20, dtype="datetime64[ns]")),
+            (Series([pd.NA] * 60), Series([NaT] * 60, dtype="datetime64[ns]")),
+            (Series([np.NaN] * 20), Series([NaT] * 20, dtype="datetime64[ns]")),
+            (Series([np.NaN] * 60), Series([NaT] * 60, dtype="datetime64[ns]")),
         ),
     )
-    def test_to_datetime_converts_null_like_to_nat(
-        self, cache, input, expected, warning
-    ):
+    def test_to_datetime_converts_null_like_to_nat(self, cache, input, expected):
         # GH35888
-        with tm.assert_produces_warning(warning, match="Could not infer format"):
-            result = to_datetime(input, cache=cache)
+        result = to_datetime(input, cache=cache)
         tm.assert_series_equal(result, expected)
 
     @pytest.mark.parametrize(
@@ -1286,8 +1279,7 @@ def test_mixed_offsets_with_native_datetime_raises(self):
         ser = Series(vals)
         assert all(ser[i] is vals[i] for i in range(len(vals)))  # GH#40111
 
-        with tm.assert_produces_warning(UserWarning, match="Could not infer format"):
-            mixed = to_datetime(ser)
+        mixed = to_datetime(ser)
         expected = Series(
             [
                 "NaT",
@@ -1849,13 +1841,11 @@ def test_to_datetime_with_apply_with_empty_str(self, cache):
 
     def test_to_datetime_empty_stt(self, cache):
         # empty string
-        with tm.assert_produces_warning(UserWarning, match="Could not infer format"):
-            result = to_datetime("", cache=cache)
+        result = to_datetime("", cache=cache)
         assert result is NaT
 
     def test_to_datetime_empty_str_list(self, cache):
-        with tm.assert_produces_warning(UserWarning, match="Could not infer format"):
-            result = to_datetime(["", ""], cache=cache)
+        result = to_datetime(["", ""], cache=cache)
         assert isna(result).all()
 
     def test_to_datetime_zero(self, cache):
@@ -2340,8 +2330,7 @@ def test_na_values_with_cache(
     def test_parsers_nat(self):
         # Test that each of several string-accepting methods return pd.NaT
         result1, _ = parsing.parse_time_string("NaT")
-        with tm.assert_produces_warning(UserWarning, match="Could not infer format"):
-            result2 = to_datetime("NaT")
+        result2 = to_datetime("NaT")
         result3 = Timestamp("NaT")
         result4 = DatetimeIndex(["NaT"])[0]
         assert result1 is NaT