Move settings to a function and add tests

tests/test_parser.py

@@ -0,0 +1,53 @@
+from __future__ import annotations
+
+import datetime
+from zoneinfo import ZoneInfo
+
+from freezegun import freeze_time
+
+from discord_reminder_bot import settings
+from discord_reminder_bot.parser import parse_time
+
+
+def test_parse_time_valid_date() -> None:
+    """Test the `parse_time` function with a valid date string."""
+    date_to_parse = "tomorrow at 5pm"
+    timezone = "UTC"
+    result: datetime.datetime | None = parse_time(date_to_parse, timezone, use_dotenv=False)
+    assert result is not None
+    assert result.tzinfo == ZoneInfo(timezone)
+
+
+def test_parse_time_no_date() -> None:
+    """Test the `parse_time` function with no date string."""
+    date_to_parse: str = ""
+    timezone = "UTC"
+    result: datetime.datetime | None = parse_time(date_to_parse, timezone, use_dotenv=False)
+    assert result is None
+
+
+def test_parse_time_no_timezone() -> None:
+    """Test the `parse_time` function with no timezone."""
+    date_to_parse = "tomorrow at 5pm"
+    result: datetime.datetime | None = parse_time(date_to_parse, use_dotenv=False)
+    assert result is not None
+    assert result.tzinfo == ZoneInfo(settings.get_timezone(use_dotenv=False))
+
+
+def test_parse_time_invalid_date() -> None:
+    """Test the `parse_time` function with an invalid date string."""
+    date_to_parse = "invalid date"
+    timezone = "UTC"
+    result: datetime.datetime | None = parse_time(date_to_parse, timezone, use_dotenv=False)
+    assert result is None
+
+
+@freeze_time("2023-01-01 12:00:00")
+def test_parse_time_invalid_timezone() -> None:
+    """Test the `parse_time` function with an invalid timezone."""
+    date_to_parse = "tomorrow at 5pm"
+    timezone = "Invalid/Timezone"
+    result: datetime.datetime | None = parse_time(date_to_parse, timezone, use_dotenv=False)
+    assert result is not None
+    assert result.tzinfo == ZoneInfo("UTC")
+    assert result == datetime.datetime(2023, 1, 2, 17, 0, tzinfo=ZoneInfo("UTC"))