Make the test helpers opt-in via a test extra (#778)

pyproject.toml

@@ -4,8 +4,8 @@ version = "3.0.0b1"
 description = "Python datetimes made easy"
 readme = "README.rst"
 requires-python = ">=3.8"
-license = {text = "MIT License"}
-authors = [{name = "Sébastien Eustace", email="sebastien@eustace.io>"}]
+license = { text = "MIT License" }
+authors = [{ name = "Sébastien Eustace", email = "sebastien@eustace.io>" }]
 keywords = ['datetime', 'date', 'time']
 
 classifiers = [
@@ -18,7 +18,7 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
 ]
 
-dependencies =[
+dependencies = [
     "python-dateutil>=2.6",
     "tzdata>=2020.1",
     'backports.zoneinfo>=0.2.1; python_version < "3.9"',
@@ -49,14 +49,14 @@ keywords = ['datetime', 'date', 'time']
 python = ">=3.8"
 python-dateutil = ">=2.6"
 "backports.zoneinfo" = { version = ">=0.2.1", python = "<3.9" }
-time-machine = { version = ">=2.6.0", markers = "implementation_name != 'pypy'" }
+time-machine = { version = ">=2.6.0", markers = "implementation_name != 'pypy'", optional = true }
 tzdata = ">=2020.1"
 importlib-resources = { version = ">=5.9.0", python = "<3.9" }
 
 [tool.poetry.group.test.dependencies]
 pytest = "^7.1.2"
 pytz = ">=2022.1"
-time-machine = "^2.7.1"
+time-machine = ">=2.6.0"
 pytest-benchmark = "^4.0.0"
 
 [tool.poetry.group.doc.dependencies]
@@ -75,7 +75,7 @@ types-pytz = ">=2022.7.1.2"
 
 [tool.poetry.group.dev.dependencies]
 babel = "^2.10.3"
-cleo = {version = "^2.0.1", python = ">=3.8,<4.0"}
+cleo = { version = "^2.0.1", python = ">=3.8,<4.0" }
 tox = "^4.0.0"
 
 [tool.poetry.group.benchmark.dependencies]
@@ -84,6 +84,9 @@ pytest-codspeed = "^1.2.2"
 [tool.poetry.group.build.dependencies]
 maturin = ">=1.0,<2.0"
 
+[tool.poetry.extras]
+test = ["time-machine"]
+
 [tool.maturin]
 module-name = "pendulum._pendulum"
 
@@ -96,18 +99,18 @@ unfixable = [
 target-version = "py38"
 line-length = 88
 extend-select = [
-    "B",   # flake8-bugbear
-    "C4",  # flake8-comprehensions
+    "B", # flake8-bugbear
+    "C4", # flake8-comprehensions
     "ERA", # flake8-eradicate/eradicate
-    "I",   # isort
-    "N",   # pep8-naming
+    "I", # isort
+    "N", # pep8-naming
     "PIE", # flake8-pie
     "PGH", # pygrep
     "RUF", # ruff checks
     "SIM", # flake8-simplify
     "TCH", # flake8-type-checking
     "TID", # flake8-tidy-imports
-    "UP",  # pyupgrade
+    "UP", # pyupgrade
 ]
 ignore = [
     "B904", # use 'raise ... from err'

src/pendulum/testing/traveller.py

@@ -18,10 +18,10 @@ def __init__(self, datetime_class: type[DateTime] = DateTime) -> None:
         self._datetime_class: type[DateTime] = datetime_class
 
     def freeze(self) -> Self:
-        raise NotImplementedError()
+        raise self._not_implemented()
 
     def travel_back(self) -> Self:
-        raise NotImplementedError()
+        raise self._not_implemented()
 
     def travel(
         self,
@@ -34,10 +34,10 @@ def travel(
         seconds: int = 0,
         microseconds: int = 0,
     ) -> Self:
-        raise NotImplementedError()
+        raise self._not_implemented()
 
     def travel_to(self, dt: DateTime, *, freeze: bool = False) -> Self:
-        raise NotImplementedError()
+        raise self._not_implemented()
 
     def __enter__(self) -> Self:
         return self
@@ -50,103 +50,123 @@ def __exit__(
     ) -> None:
         ...
 
+    def _not_implemented(self) -> NotImplementedError:
+        return NotImplementedError()
+
 
 if not PYPY:
-    import time_machine
+    try:
+        import time_machine
+    except ImportError:
+        time_machine = None  # type: ignore[assignment]
 
-    class Traveller(BaseTraveller):
-        def __init__(self, datetime_class: type[DateTime] = DateTime) -> None:
-            super().__init__(datetime_class)
+    if time_machine is not None:
 
-            self._started: bool = False
-            self._traveller: time_machine.travel | None = None
-            self._coordinates: time_machine.Coordinates | None = None
+        class Traveller(BaseTraveller):
+            def __init__(self, datetime_class: type[DateTime] = DateTime) -> None:
+                super().__init__(datetime_class)
 
-        def freeze(self) -> Self:
-            if self._started:
-                cast(time_machine.Coordinates, self._coordinates).move_to(
-                    self._datetime_class.now(), tick=False
-                )
-            else:
-                self._start(freeze=True)
+                self._started: bool = False
+                self._traveller: time_machine.travel | None = None
+                self._coordinates: time_machine.Coordinates | None = None
 
-            return self
+            def freeze(self) -> Self:
+                if self._started:
+                    cast(time_machine.Coordinates, self._coordinates).move_to(
+                        self._datetime_class.now(), tick=False
+                    )
+                else:
+                    self._start(freeze=True)
 
-        def travel_back(self) -> Self:
-            if not self._started:
                 return self
 
-            cast(time_machine.travel, self._traveller).stop()
-            self._coordinates = None
-            self._traveller = None
-            self._started = False
-
-            return self
-
-        def travel(
-            self,
-            years: int = 0,
-            months: int = 0,
-            weeks: int = 0,
-            days: int = 0,
-            hours: int = 0,
-            minutes: int = 0,
-            seconds: int = 0,
-            microseconds: int = 0,
-            *,
-            freeze: bool = False,
-        ) -> Self:
-            self._start(freeze=freeze)
-
-            cast(time_machine.Coordinates, self._coordinates).move_to(
-                self._datetime_class.now().add(
-                    years=years,
-                    months=months,
-                    weeks=weeks,
-                    days=days,
-                    hours=hours,
-                    minutes=minutes,
-                    seconds=seconds,
-                    microseconds=microseconds,
+            def travel_back(self) -> Self:
+                if not self._started:
+                    return self
+
+                cast(time_machine.travel, self._traveller).stop()
+                self._coordinates = None
+                self._traveller = None
+                self._started = False
+
+                return self
+
+            def travel(
+                self,
+                years: int = 0,
+                months: int = 0,
+                weeks: int = 0,
+                days: int = 0,
+                hours: int = 0,
+                minutes: int = 0,
+                seconds: int = 0,
+                microseconds: int = 0,
+                *,
+                freeze: bool = False,
+            ) -> Self:
+                self._start(freeze=freeze)
+
+                cast(time_machine.Coordinates, self._coordinates).move_to(
+                    self._datetime_class.now().add(
+                        years=years,
+                        months=months,
+                        weeks=weeks,
+                        days=days,
+                        hours=hours,
+                        minutes=minutes,
+                        seconds=seconds,
+                        microseconds=microseconds,
+                    )
                 )
-            )
 
-            return self
+                return self
 
-        def travel_to(self, dt: DateTime, *, freeze: bool = False) -> Self:
-            self._start(freeze=freeze)
+            def travel_to(self, dt: DateTime, *, freeze: bool = False) -> Self:
+                self._start(freeze=freeze)
 
-            cast(time_machine.Coordinates, self._coordinates).move_to(dt)
+                cast(time_machine.Coordinates, self._coordinates).move_to(dt)
 
-            return self
+                return self
 
-        def _start(self, freeze: bool = False) -> None:
-            if self._started:
-                return
+            def _start(self, freeze: bool = False) -> None:
+                if self._started:
+                    return
 
-            if not self._traveller:
-                self._traveller = time_machine.travel(
-                    self._datetime_class.now(), tick=not freeze
-                )
+                if not self._traveller:
+                    self._traveller = time_machine.travel(
+                        self._datetime_class.now(), tick=not freeze
+                    )
 
-            self._coordinates = self._traveller.start()
+                self._coordinates = self._traveller.start()
 
-            self._started = True
+                self._started = True
 
-        def __enter__(self) -> Self:
-            self._start()
+            def __enter__(self) -> Self:
+                self._start()
 
-            return self
+                return self
 
-        def __exit__(
-            self,
-            exc_type: type[BaseException] | None,
-            exc_val: BaseException | None,
-            exc_tb: TracebackType,
-        ) -> None:
-            self.travel_back()
+            def __exit__(
+                self,
+                exc_type: type[BaseException] | None,
+                exc_val: BaseException | None,
+                exc_tb: TracebackType,
+            ) -> None:
+                self.travel_back()
+
+    else:
+
+        class Traveller(BaseTraveller):  # type: ignore[no-redef]
+            def _not_implemented(self) -> NotImplementedError:
+                return NotImplementedError(
+                    "Time travelling is an optional feature. "
+                    'You can add it by installing Pendulum with the "test" extra.'
+                )
 
 else:
 
     class Traveller(BaseTraveller):  # type: ignore[no-redef]
-        ...
+        def _not_implemented(self) -> NotImplementedError:
+            return NotImplementedError(
+                "Time travelling is not supported on the PyPy Python implementation."
+            )