Merge 03b917d into 1c12018

src/repository_orm/adapters/data/cache.py

@@ -1,30 +1,42 @@
 """Define the cache of the data repositories."""
 
-from typing import Dict, List, Type, TypeVar
+from typing import Any, Dict, List, Type, TypeVar
 
-from ...model import Entity, EntityID
+from ...model import Entity as EntityModel
+from ...model import EntityID
 
+Entity = TypeVar("Entity", bound=EntityModel)
 CacheEntry = Dict[EntityID, Entity]
-EntityOrEntities = TypeVar("EntityOrEntities", List[Entity], Entity)
+EntityOrEntities = TypeVar("EntityOrEntities", List[EntityModel], EntityModel)
 
 
 class Cache:
-    """Define the cache of a repository."""
+    """Define the cache of a repository.
+
+    The entries are saved in the `cache` attribute under a dictionary similar to:
+    {
+        Model_1: {
+            Entity_1_ID: Entity_1,
+            Entity_2_ID: Entity_2,
+        },
+    }
+
+    """
 
     def __init__(self) -> None:
         """Initialize the class."""
-        self.cache: Dict[Type[Entity], CacheEntry] = {}
+        self.cache: Dict[Type[EntityModel], CacheEntry[Any]] = {}
 
     def add(self, entity_or_entities: EntityOrEntities) -> None:
         """Add an entity to the cache."""
-        if isinstance(entity_or_entities, Entity):
+        if isinstance(entity_or_entities, EntityModel):
             entities = [entity_or_entities]
         else:
             entities = entity_or_entities
 
         for entity in entities:
             self.cache.setdefault(type(entity), {})
-            self.cache[type(entity)].setdefault(entity.id_, entity)
+            self.cache[type(entity)].setdefault(entity.id_, entity.copy())
 
     def get(self, entity: Entity) -> Entity:
         """Return the cached value of an entity."""

tests/unit/test_cache.py

@@ -0,0 +1,22 @@
+"""Test the implementation of the data repository cache."""
+
+from tests.cases.model import Entity
+
+from repository_orm.adapters.data.cache import Cache
+
+
+def test_cache_is_immutable_on_external_changes() -> None:
+    """
+    Given: An entry in the cache
+    When: an external function changes the entity
+    Then: the cached version is unchanged
+    """
+    entity = Entity(name="Original name")
+    cache = Cache()
+    cache.add(entity)
+    entity.name = "Modified name"
+
+    result = cache.get(entity)
+
+    assert result.name == "Original name"
+    assert not cache.entity_has_not_changed(entity)