Don't eagerly load the Locale, nor pytest until it's needed.

src/pendulum/__init__.py

@@ -2,6 +2,8 @@
 
 import datetime as _datetime
 
+from functools import cache
+from typing import TYPE_CHECKING
 from typing import Any
 from typing import Union
 from typing import cast
@@ -30,7 +32,6 @@
 from pendulum.helpers import week_starts_at
 from pendulum.interval import Interval
 from pendulum.parser import parse as parse
-from pendulum.testing.traveller import Traveller
 from pendulum.time import Time
 from pendulum.tz import UTC
 from pendulum.tz import fixed_timezone
@@ -334,17 +335,43 @@ def interval(
     return Interval(start, end, absolute=absolute)
 
 
-# Testing
+if TYPE_CHECKING:
+    from pendulum.testing.traveller import Traveller
 
-_traveller = Traveller(DateTime)
+    _traveller = Traveller(DateTime)
+    freeze = _traveller.freeze
+    travel = _traveller.travel
+    travel_to = _traveller.travel_to
+    travel_back = _traveller.travel_back
+else:
+    # We do this in an if-not-typing block so we don't have to duplicate the function signatures.
+    @cache
+    def _traveller() -> Traveller:
+        # Lazy load this, so we don't eagerly load Pytest if we don't need to
+        from pendulum.testing.traveller import Traveller
 
-freeze = _traveller.freeze
-travel = _traveller.travel
-travel_to = _traveller.travel_to
-travel_back = _traveller.travel_back
+        return Traveller(DateTime)
+
+    def freeze(*args, **kwargs) -> Traveller:
+        return _traveller().freeze(*args, **kwargs)
+
+    def travel(*args, **kwargs):
+        _traveller().travel(*args, **kwargs)
+
+    def travel_to(*args, **kwargs):
+        _traveller().travel_to(*args, **kwargs)
+
+    def travel_back(*args, **kwargs):
+        _traveller().travel_back(*args, **kwargs)
 
 
 def __getattr__(name: str) -> Any:
+    if name == "Traveller":
+        # This wasn't in `__all__`, but it was defined before, so keep it for back compat
+        from pendulum.testing.traveller import Traveller
+
+        return Traveller
+
     if name == "__version__":
         import importlib.metadata
         import warnings

src/pendulum/helpers.py

@@ -6,23 +6,27 @@
 from datetime import date
 from datetime import datetime
 from datetime import timedelta
+from functools import cache
 from math import copysign
 from typing import TYPE_CHECKING
+from typing import Any
 from typing import TypeVar
 from typing import overload
 
 import pendulum
 
 from pendulum.constants import DAYS_PER_MONTHS
 from pendulum.day import WeekDay
-from pendulum.formatting.difference_formatter import DifferenceFormatter
 from pendulum.locales.locale import Locale
 
 
 if TYPE_CHECKING:
     # Prevent import cycles
     from pendulum.duration import Duration
 
+    # LazyLoaded
+    from pendulum.formatting.difference_formatter import DifferenceFormatter
+
 with_extensions = os.getenv("PENDULUM_EXTENSIONS", "1") == "1"
 
 _DT = TypeVar("_DT", bound=datetime)
@@ -48,7 +52,7 @@
     from pendulum._helpers import precise_diff  # type: ignore[assignment]
     from pendulum._helpers import week_day
 
-difference_formatter = DifferenceFormatter()
+difference_formatter: DifferenceFormatter
 
 
 @overload
@@ -164,7 +168,7 @@ def format_diff(
     if locale is None:
         locale = get_locale()
 
-    return difference_formatter.format(diff, is_now, absolute, locale)
+    return _difference_formatter().format(diff, is_now, absolute, locale)
 
 
 def _sign(x: float) -> int:
@@ -202,6 +206,19 @@ def week_ends_at(wday: WeekDay) -> None:
     pendulum._WEEK_ENDS_AT = wday
 
 
+@cache
+def _difference_formatter() -> DifferenceFormatter:
+    from pendulum.formatting.difference_formatter import DifferenceFormatter
+
+    return DifferenceFormatter()
+
+
+def __getattr__(name: str) -> Any:
+    if name == "difference_formatter":
+        return _difference_formatter()
+    raise AttributeError(name)
+
+
 __all__ = [
     "PreciseDiff",
     "add_duration",

src/pendulum/locales/locale.py

@@ -2,7 +2,6 @@
 
 import re
 
-from importlib import import_module, resources
 from pathlib import Path
 from typing import Any
 from typing import ClassVar
@@ -24,6 +23,8 @@ def __init__(self, locale: str, data: Any) -> None:
 
     @classmethod
     def load(cls, locale: str | Locale) -> Locale:
+        from importlib import import_module, resources
+
         if isinstance(locale, Locale):
             return locale