python-dependency-injector/examples/overrides.py
2015-01-28 13:08:54 +02:00

61 lines
1.4 KiB
Python

"""
Concept example of objects overrides.
"""
from objects import AbstractCatalog, overrides
from objects.providers import Singleton, NewInstance
from objects.injections import InitArg, Attribute
import sqlite3
# Some example class.
class ObjectA(object):
def __init__(self, db):
self.db = db
# Mock of example class.
class ObjectAMock(ObjectA):
pass
# Catalog of objects providers.
class Catalog(AbstractCatalog):
"""
Objects catalog.
"""
database = Singleton(sqlite3.Connection,
InitArg('database', ':memory:'),
Attribute('row_factory', sqlite3.Row))
""" :type: (objects.Provider) -> sqlite3.Connection """
object_a = NewInstance(ObjectA,
InitArg('db', database))
""" :type: (objects.Provider) -> ObjectA """
# Overriding Catalog by SandboxCatalog with some mocks.
@overrides(Catalog)
class SandboxCatalog(Catalog):
"""
Sandbox objects catalog with some mocks.
"""
object_a = NewInstance(ObjectAMock,
InitArg('db', Catalog.database))
""" :type: (objects.Provider) -> ObjectA """
# Catalog static provides.
a1 = Catalog.object_a()
a2 = Catalog.object_a()
# Some asserts.
assert isinstance(a1, ObjectAMock)
assert isinstance(a2, ObjectAMock)
assert a1 is not a2
assert a1.db is a2.db is Catalog.database()