allow_empty support for datetime types

pandas_schema/validation.py

@@ -9,7 +9,7 @@
 from . import column
 from .validation_warning import ValidationWarning
 from .errors import PanSchArgumentError
-from pandas.api.types import is_categorical_dtype, is_numeric_dtype
+from pandas.api.types import is_categorical_dtype, is_datetime64_any_dtype, is_numeric_dtype
 
 
 class _BaseValidation:
@@ -85,8 +85,8 @@ def get_errors(self, series: pd.Series, column: 'column.Column'):
         simple_validation = ~self.validate(series)
         if column.allow_empty:
             # Failing results are those that are not empty, and fail the validation
-            # explicitly check to make sure the series isn't a category because issubdtype will FAIL if it is
-            if is_categorical_dtype(series) or is_numeric_dtype(series):
+            # explicitly check to make sure the series isn't a category/datetime because issubdtype will FAIL if it is
+            if is_categorical_dtype(series) or is_datetime64_any_dtype(series) or is_numeric_dtype(series):
                 validated = ~series.isnull() & simple_validation
             else:
                 validated = (series.str.len() > 0) & simple_validation

test/test_validation.py

@@ -688,3 +688,27 @@ def test_invalid_elements(self):
         errors = self.validator.get_errors(pd.Series(['aa', 'bb', 'd'], dtype='category'),
                                            Column('', allow_empty=True))
         self.assertEqual(len(errors), 3)
+
+class GetErrorAllowEmptyDatetimeTests(ValidationTestBase):
+    """
+    Tests for datetime valued columns where allow_empty=True
+    """
+
+    def setUp(self):
+        match_val = datetime.datetime(2020, 11, 1)
+        self.validator = CustomSeriesValidation(lambda s: s == match_val, 'did not match target date')
+
+    def test_valid(self):
+        series = pd.Series(['2020-11-01'], dtype='datetime64[ns]')
+        errors = self.validator.get_errors(series, Column('', allow_empty=True))
+        self.assertEqual(len(errors), 0)
+
+    def test_valid_invalid(self):
+        series = pd.Series(['2020-11-01', '2025-01-01'], dtype='datetime64[ns]')
+        errors = self.validator.get_errors(series, Column('', allow_empty=True))
+        self.assertEqual(len(errors), 1)
+
+    def test_valid_invalid_empty(self):
+        series = pd.Series(['2020-11-01', '2025-01-01', pd.NaT, np.NaN], dtype='datetime64[ns]')
+        errors = self.validator.get_errors(series, Column('', allow_empty=True))
+        self.assertEqual(len(errors), 1)