feat($demo): support strategy design pattern in Python

python_boilerplate/demo/strategy_design_pattern_usage.py

@@ -0,0 +1,51 @@
+from loguru import logger
+
+
+class BaseStrategy:
+    _strategies: list["BaseStrategy"] = []
+
+    @classmethod
+    def init(cls) -> None:
+        if len(cls._strategies) > 0:
+            return
+        strategy_classes = BaseStrategy.__subclasses__()
+        cls._strategies = [
+            strategy_class.__new__(strategy_class)
+            for strategy_class in strategy_classes
+        ]
+
+    def strategy_name(self) -> str:
+        return self.__class__.__name__
+
+    def matches(self, data_input: str) -> bool:
+        raise NotImplementedError(
+            f"Function `{self.matches.__qualname__}` is not implemented"
+        )
+
+    def execute(self, data_input: str) -> None:
+        raise NotImplementedError(
+            f"Function `{self.execute.__qualname__}` is not implemented"
+        )
+
+    @classmethod
+    def iter_execute(cls, data_input: str) -> None:
+        strategies = list(filter(lambda x: x.matches(data_input), cls._strategies))
+        if len(strategies) != 1:
+            raise ValueError("No supported strategies found")
+        strategies[0].execute(data_input)
+
+
+class StrategyOne(BaseStrategy):
+    def matches(self, data_input: str) -> bool:
+        return "one" in data_input
+
+    def execute(self, data_input: str) -> None:
+        logger.info(f"Executing {self.strategy_name()} with: {data_input}")
+
+
+class StrategyTwo(BaseStrategy):
+    def matches(self, data_input: str) -> bool:
+        return "two" in data_input
+
+    def execute(self, data_input: str) -> None:
+        logger.info(f"Executing {self.strategy_name()} with: {data_input}")

tests/demo/test_strategy_design_pattern_usage.py

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+import pytest
+from loguru import logger
+
+from python_boilerplate.demo.strategy_design_pattern_usage import BaseStrategy
+
+
+@pytest.fixture(scope="session", autouse=True)
+def setup() -> None:
+    logger.info("Initializing tests...")
+    BaseStrategy.init()
+
+
+def test_strategies_when_matches() -> None:
+    BaseStrategy.iter_execute("Data for strategy one")
+    BaseStrategy.iter_execute("Data for strategy two")
+
+
+def test_strategies_when_not_matches() -> None:
+    with pytest.raises(ValueError) as exc_info:
+        BaseStrategy.iter_execute("Data that doesn't match strategy")
+    assert exc_info is not None
+    logger.warning(f"Expected exception: {exc_info.value}")
+
+
+def test_base_strategy() -> None:
+    strategy = BaseStrategy()
+    strategy_name = strategy.strategy_name()
+    assert strategy_name is not None
+    assert strategy_name == BaseStrategy.__name__
+    with pytest.raises(NotImplementedError) as exc_info_for_matches:
+        strategy.matches("any")
+    assert exc_info_for_matches is not None
+    with pytest.raises(NotImplementedError) as exc_info_for_execute:
+        strategy.execute("any")
+    assert exc_info_for_execute is not None
+
+
+def test_call_twice_init() -> None:
+    try:
+        BaseStrategy.init()
+        BaseStrategy.init()
+        strategies = BaseStrategy._strategies
+        assert strategies is not None
+        assert len(strategies) == 2
+        logger.info(f"Strategies: {strategies}")
+    except Exception as e:
+        assert False, f"Unexpected exception raised: {e}"