Harrison/datetime parser (#4693)

Co-authored-by: Jacob Valdez <jacobfv@msn.com>
Co-authored-by: Jacob Valdez <jacob.valdez@limboid.ai>
Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com>

tests/unit_tests/output_parsers/test_datetime_parser.py

@@ -0,0 +1,49 @@
+from datetime import datetime
+from time import sleep
+
+from langchain.output_parsers.datetime import DatetimeOutputParser
+
+
+def test_datetime_output_parser_parse() -> None:
+    parser = DatetimeOutputParser()
+
+    # Test valid input
+    date = datetime.now()
+    datestr = date.strftime(parser.format)
+    result = parser.parse(datestr)
+    assert result == date
+
+    # Test valid input
+    parser.format = "%Y-%m-%dT%H:%M:%S"
+    date = datetime.now()
+    datestr = date.strftime(parser.format)
+    result = parser.parse(datestr)
+    assert (
+        result.year == date.year
+        and result.month == date.month
+        and result.day == date.day
+        and result.hour == date.hour
+        and result.minute == date.minute
+        and result.second == date.second
+    )
+
+    # Test valid input
+    parser.format = "%H:%M:%S"
+    date = datetime.now()
+    datestr = date.strftime(parser.format)
+    result = parser.parse(datestr)
+    assert (
+        result.hour == date.hour
+        and result.minute == date.minute
+        and result.second == date.second
+    )
+
+    # Test invalid input
+    try:
+        sleep(0.001)
+        datestr = date.strftime(parser.format)
+        result = parser.parse(datestr)
+        assert result == date
+        assert False, "Should have raised AssertionError"
+    except AssertionError:
+        pass