Add validation for errors parameter in cudf.to_datetime (#8068)

This PR checks for the parameter being passed to `errors` in `cudf.to_datetime`.

This PR only partially addresses #8010

Authors:
  - GALI PREM SAGAR (https://github.com/galipremsagar)

Approvers:
  - Ram (Ramakrishna Prabhu) (https://github.com/rgsl888prabhu)

URL: #8068

python/cudf/cudf/core/tools/datetimes.py

@@ -104,6 +104,13 @@ def to_datetime(
     >>> cudf.to_datetime(1490195805433502912, unit='ns')
     numpy.datetime64('1780-11-20T01:02:30.494253056')
     """
+    if errors not in {"ignore", "raise", "coerce", "warn"}:
+        raise ValueError(
+            f"errors parameter has to be either one of: "
+            f"{['ignore', 'raise', 'coerce', 'warn']}, found: "
+            f"{errors}"
+        )
+
     if arg is None:
         return None
 

python/cudf/cudf/tests/test_datetime.py

@@ -1248,3 +1248,17 @@ def test_datetime_infer_format(data, dtype):
 def test_dateoffset_instance_subclass_check():
     assert not issubclass(pd.DateOffset, cudf.DateOffset)
     assert not isinstance(pd.DateOffset(), cudf.DateOffset)
+
+
+def test_datetime_to_datetime_error():
+    assert_exceptions_equal(
+        lfunc=pd.to_datetime,
+        rfunc=cudf.to_datetime,
+        lfunc_args_and_kwargs=(["02-Oct-2017 09:30", "%d-%B-%Y %H:%M"],),
+        rfunc_args_and_kwargs=(["02-Oct-2017 09:30", "%d-%B-%Y %H:%M"],),
+        check_exception_type=False,
+        expected_error_message=re.escape(
+            "errors parameter has to be either one of: ['ignore', 'raise', "
+            "'coerce', 'warn'], found: %d-%B-%Y %H:%M"
+        ),
+    )