Allow whitespace in duration strings and update tests

https://github.com/python-discord/bot/issues/446

After review feedback and a discussion in the dev-core team, I've
changed a couple of things:

- Allow a space between amount and unit in the duration string;

- Allow a space between different units in the duration string;

- Remove the old ExpirationDate converter completely;

- Remove the dependency `dateparser` from the Pipfile;

- Update tests for the two types of optional spaces;

- Change the test for valid cases to a more readable format;

This PR closes #446

1 files changed, 66 insertions, 47 deletions

diff --git a/tests/test_converters.py b/tests/test_converters.py
index 3cf00035f..35fc5d88e 100644
--- a/tests/test_converters.py
+++ b/tests/test_converters.py
@@ -3,11 +3,11 @@ import datetime
 from unittest.mock import MagicMock, patch
 
 import pytest
+from dateutil.relativedelta import relativedelta
 from discord.ext.commands import BadArgument
 
 from bot.converters import (
     Duration,
-    ExpirationDate,
     TagContentConverter,
     TagNameConverter,
     ValidPythonIdentifier,
@@ -17,18 +17,6 @@ from bot.converters import (
 @pytest.mark.parametrize(
     ('value', 'expected'),
     (
-        # sorry aliens
-        ('2199-01-01T00:00:00', datetime.datetime(2199, 1, 1)),
-    )
-)
-def test_expiration_date_converter_for_valid(value: str, expected: datetime.datetime):
-    converter = ExpirationDate()
-    assert asyncio.run(converter.convert(None, value)) == expected
-
-
[email protected](
-    ('value', 'expected'),
-    (
         ('hello', 'hello'),
         ('  h ello  ', 'h ello')
     )
@@ -97,46 +85,68 @@ def test_valid_python_identifier_for_invalid(value: str):
 FIXED_UTC_NOW = datetime.datetime.fromisoformat('2019-01-01T00:00:00')
 
 
[email protected](
-    ('duration', 'expected'),
-    (
[email protected](
+    params=(
         # Simple duration strings
-        ('1Y', datetime.datetime.fromisoformat('2020-01-01T00:00:00')),
-        ('1y', datetime.datetime.fromisoformat('2020-01-01T00:00:00')),
-        ('1year', datetime.datetime.fromisoformat('2020-01-01T00:00:00')),
-        ('1years', datetime.datetime.fromisoformat('2020-01-01T00:00:00')),
-        ('1m', datetime.datetime.fromisoformat('2019-02-01T00:00:00')),
-        ('1month', datetime.datetime.fromisoformat('2019-02-01T00:00:00')),
-        ('1months', datetime.datetime.fromisoformat('2019-02-01T00:00:00')),
-        ('1w', datetime.datetime.fromisoformat('2019-01-08T00:00:00')),
-        ('1W', datetime.datetime.fromisoformat('2019-01-08T00:00:00')),
-        ('1week', datetime.datetime.fromisoformat('2019-01-08T00:00:00')),
-        ('1weeks', datetime.datetime.fromisoformat('2019-01-08T00:00:00')),
-        ('1d', datetime.datetime.fromisoformat('2019-01-02T00:00:00')),
-        ('1D', datetime.datetime.fromisoformat('2019-01-02T00:00:00')),
-        ('1day', datetime.datetime.fromisoformat('2019-01-02T00:00:00')),
-        ('1days', datetime.datetime.fromisoformat('2019-01-02T00:00:00')),
-        ('1h', datetime.datetime.fromisoformat('2019-01-01T01:00:00')),
-        ('1H', datetime.datetime.fromisoformat('2019-01-01T01:00:00')),
-        ('1hour', datetime.datetime.fromisoformat('2019-01-01T01:00:00')),
-        ('1hours', datetime.datetime.fromisoformat('2019-01-01T01:00:00')),
-        ('1M', datetime.datetime.fromisoformat('2019-01-01T00:01:00')),
-        ('1minute', datetime.datetime.fromisoformat('2019-01-01T00:01:00')),
-        ('1minutes', datetime.datetime.fromisoformat('2019-01-01T00:01:00')),
-        ('1s', datetime.datetime.fromisoformat('2019-01-01T00:00:01')),
-        ('1S', datetime.datetime.fromisoformat('2019-01-01T00:00:01')),
-        ('1second', datetime.datetime.fromisoformat('2019-01-01T00:00:01')),
-        ('1seconds', datetime.datetime.fromisoformat('2019-01-01T00:00:01')),
+        ('1Y', {"years": 1}),
+        ('1y', {"years": 1}),
+        ('1year', {"years": 1}),
+        ('1years', {"years": 1}),
+        ('1m', {"months": 1}),
+        ('1month', {"months": 1}),
+        ('1months', {"months": 1}),
+        ('1w', {"weeks": 1}),
+        ('1W', {"weeks": 1}),
+        ('1week', {"weeks": 1}),
+        ('1weeks', {"weeks": 1}),
+        ('1d', {"days": 1}),
+        ('1D', {"days": 1}),
+        ('1day', {"days": 1}),
+        ('1days', {"days": 1}),
+        ('1h', {"hours": 1}),
+        ('1H', {"hours": 1}),
+        ('1hour', {"hours": 1}),
+        ('1hours', {"hours": 1}),
+        ('1M', {"minutes": 1}),
+        ('1minute', {"minutes": 1}),
+        ('1minutes', {"minutes": 1}),
+        ('1s', {"seconds": 1}),
+        ('1S', {"seconds": 1}),
+        ('1second', {"seconds": 1}),
+        ('1seconds', {"seconds": 1}),
 
         # Complex duration strings
-        ('1y1m1w1d1H1M1S', datetime.datetime.fromisoformat('2020-02-09T01:01:01')),
-        ('5y100S', datetime.datetime.fromisoformat('2024-01-01T00:01:40')),
-        ('2w28H', datetime.datetime.fromisoformat('2019-01-16T04:00:00')),
+        (
+            '1y1m1w1d1H1M1S',
+            {
+                "years": 1,
+                "months": 1,
+                "weeks": 1,
+                "days": 1,
+                "hours": 1,
+                "minutes": 1,
+                "seconds": 1
+            }
+        ),
+        ('5y100S', {"years": 5, "seconds": 100}),
+        ('2w28H', {"weeks": 2, "hours": 28}),
+
+        # Duration strings with spaces
+        ('1 year 2 months', {"years": 1, "months": 2}),
+        ('1d 2H', {"days": 1, "hours": 2}),
+        ('1 week2 days', {"weeks": 1, "days": 2}),
     )
 )
-def test_duration_converter_for_valid(duration: str, expected: datetime):
-    converter = Duration()
+def create_future_datetime(request):
+    """Yields duration string and target datetime.datetime object."""
+    duration, duration_dict = request.param
+    future_datetime = FIXED_UTC_NOW + relativedelta(**duration_dict)
+    yield duration, future_datetime
+
 
+def test_duration_converter_for_valid(create_future_datetime: tuple):
+    converter = Duration()
+    duration, expected = create_future_datetime
     with patch('bot.converters.datetime') as mock_datetime:
         mock_datetime.utcnow.return_value = FIXED_UTC_NOW
         assert asyncio.run(converter.convert(None, duration)) == expected
@@ -149,6 +159,10 @@ def test_duration_converter_for_valid(duration: str, expected: datetime):
         ('1d1w'),
         ('1s1y'),
 
+        # Duplicated units
+        ('1 year 2 years'),
+        ('1 M 10 minutes'),
+
         # Unknown substrings
         ('1MVes'),
         ('1y3breads'),
@@ -156,6 +170,11 @@ def test_duration_converter_for_valid(duration: str, expected: datetime):
         # Missing amount
         ('ym'),
 
+        # Incorrect whitespace
+        (" 1y"),
+        ("1S "),
+        ("1y  1m"),
+
         # Garbage
         ('Guido van Rossum'),
         ('lemon lemon lemon lemon lemon lemon lemon'),