test(middleware): add middleware tests

Author: sassanh

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## Version 0.14.5
+
+- test(middleware): add middleware tests
+
 ## Version 0.14.4
 
 - refactor(test): add the counter id of the failed snapshot to the error message

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "python-redux"
-version = "0.14.4"
+version = "0.14.5"
 description = "Redux implementation for Python"
 authors = ["Sassan Haradji <[email protected]>"]
 license = "Apache-2.0"
@@ -50,7 +50,7 @@ inline-quotes = "single"
 multiline-quotes = "double"
 
 [tool.ruff.lint.per-file-ignores]
-"tests/*" = ["S101", "PLR0915"]
+"tests/*" = ["S101", "PLR0915", "PLR2004"]
 
 [tool.ruff.format]
 quote-style = 'single'

redux/main.py

@@ -109,33 +109,27 @@ def _call_listeners(self: Store[State, Action, Event], state: State) -> None:
                 self._create_task(result)
 
     def _run_actions(self: Store[State, Action, Event]) -> None:
-        while True:
-            if len(self._actions) == 0:
-                return
+        while len(self._actions) > 0:
             action = self._actions.pop(0)
             if action is not None:
-                break
-        result = self.reducer(self._state, action)
-        if is_complete_reducer_result(result):
-            self._state = result.state
-            self._call_listeners(self._state)
-            self.dispatch([*(result.actions or []), *(result.events or [])])
-        elif is_state_reducer_result(result):
-            self._state = result
-            self._call_listeners(self._state)
-
-        if isinstance(action, FinishAction):
-            self.dispatch(cast(Event, FinishEvent()))
+                result = self.reducer(self._state, action)
+                if is_complete_reducer_result(result):
+                    self._state = result.state
+                    self._call_listeners(self._state)
+                    self.dispatch([*(result.actions or []), *(result.events or [])])
+                elif is_state_reducer_result(result):
+                    self._state = result
+                    self._call_listeners(self._state)
+
+                if isinstance(action, FinishAction):
+                    self.dispatch(cast(Event, FinishEvent()))
 
     def _run_event_handlers(self: Store[State, Action, Event]) -> None:
-        while True:
-            if len(self._events) == 0:
-                return
+        while len(self._events) > 0:
             event = self._events.pop(0)
             if event is not None:
-                break
-        for event_handler in self._event_handlers[type(event)].copy():
-            self._event_handlers_queue.put_nowait((event_handler, event))
+                for event_handler in self._event_handlers[type(event)].copy():
+                    self._event_handlers_queue.put_nowait((event_handler, event))
 
     def run(self: Store[State, Action, Event]) -> None:
         """Run the store."""

tests/test_middleware.py

@@ -0,0 +1,178 @@
+# ruff: noqa: D100, D101, D102, D103, D104, D107
+
+from __future__ import annotations
+
+from dataclasses import replace
+
+import pytest
+from immutable import Immutable
+
+from redux.basic_types import (
+    BaseAction,
+    BaseEvent,
+    CompleteReducerResult,
+    CreateStoreOptions,
+    FinishAction,
+    FinishEvent,
+    InitAction,
+    InitializationActionError,
+)
+from redux.main import Store
+
+
+class StateType(Immutable):
+    value: int
+
+
+class IncrementAction(BaseAction): ...
+
+
+class DecrementAction(BaseAction): ...
+
+
+class SomeEvent(BaseEvent): ...
+
+
+Action = IncrementAction | DecrementAction | InitAction | FinishAction
+
+
+def reducer(
+    state: StateType | None,
+    action: Action,
+) -> StateType | CompleteReducerResult[StateType, Action, SomeEvent | FinishEvent]:
+    if state is None:
+        if isinstance(action, InitAction):
+            return StateType(value=0)
+        raise InitializationActionError(action)
+
+    if isinstance(action, IncrementAction):
+        return replace(state, value=state.value + 1)
+
+    if isinstance(action, DecrementAction):
+        return replace(state, value=state.value - 1)
+
+    return state
+
+
+class StoreType(Store[StateType, Action, FinishEvent | SomeEvent]):
+    @property
+    def state(self: StoreType) -> StateType | None:
+        return self._state
+
+
+@pytest.fixture()
+def store() -> StoreType:
+    return StoreType(reducer, options=CreateStoreOptions(auto_init=True))
+
+
+def test_identity_action_middleware(store: StoreType) -> None:
+    calls = []
+
+    def middleware(action: Action) -> Action:
+        calls.append(action)
+        if isinstance(action, IncrementAction):
+            return DecrementAction()
+        return action
+
+    store.register_action_middleware(middleware)
+
+    actions = [
+        IncrementAction(),
+        IncrementAction(),
+        FinishAction(),
+    ]
+
+    def check() -> None:
+        assert calls == actions
+        assert store.state
+        assert store.state.value == -2
+
+    store.subscribe_event(FinishEvent, check)
+
+    for action in actions:
+        store.dispatch(action)
+
+
+def test_cancelling_action_middleware(store: StoreType) -> None:
+    calls = []
+
+    def middleware(action: Action) -> Action | None:
+        calls.append(action)
+        if len(calls) == 1:
+            return None
+        return action
+
+    store.register_action_middleware(middleware)
+
+    actions = [
+        IncrementAction(),
+        IncrementAction(),
+        FinishAction(),
+    ]
+
+    def check() -> None:
+        assert store.state
+        assert store.state.value == 1
+
+    store.subscribe_event(FinishEvent, check)
+
+    for action in actions:
+        store.dispatch(action)
+
+
+def test_identity_event_middlewares(store: StoreType) -> None:
+    calls = []
+
+    def middleware(event: SomeEvent) -> SomeEvent | FinishEvent:
+        calls.append(event)
+        if len(calls) == 2:
+            return FinishEvent()
+        return event
+
+    store.register_event_middleware(middleware)
+
+    events = [
+        SomeEvent(),
+        SomeEvent(),
+        SomeEvent(),
+    ]
+
+    def check() -> None:
+        assert calls == events
+
+    store.subscribe_event(FinishEvent, check)
+
+    for event in events:
+        store.dispatch(event)
+
+
+def test_cancelling_event_middlewares(store: StoreType) -> None:
+    calls = []
+
+    def middleware(event: SomeEvent | FinishEvent) -> SomeEvent | FinishEvent | None:
+        calls.append(event)
+        if len(calls) == 1 and isinstance(event, SomeEvent):
+            return None
+        return event
+
+    side_effect_calls = []
+
+    def some_side_effect(event: SomeEvent) -> None:
+        side_effect_calls.append(event)
+
+    store.register_event_middleware(middleware)
+
+    events = [
+        SomeEvent(),
+        SomeEvent(),
+    ]
+
+    def check() -> None:
+        assert side_effect_calls == events[1:2]
+
+    store.subscribe_event(SomeEvent, some_side_effect)
+    store.subscribe_event(FinishEvent, check)
+
+    for event in events:
+        store.dispatch(event)
+    store.dispatch(FinishAction())