Add option to create an instance with non-shared data

README.rst

@@ -75,6 +75,8 @@ test you run, be sure to call `r.flushall()` in your
         # Clear data in fakenewsredis.
         self.r.flushall()
 
+Alternatively, you can create an instance that does not share data with other
+instances, by passing `singleton=False` to the constructor.
 
 Fakenewsredis implements the same interface as `redis-py`_, the
 popular redis client for python, and models the responses

fakenewsredis.py

@@ -269,10 +269,14 @@ def from_url(cls, url, db=None, **kwargs):
         return cls(db=db, **kwargs)
 
     def __init__(self, db=0, charset='utf-8', errors='strict',
-                 decode_responses=False, **kwargs):
-        if db not in DATABASES:
-            DATABASES[db] = _ExpiringDict()
-        self._db = DATABASES[db]
+                 decode_responses=False, singleton=True, **kwargs):
+        if singleton:
+            self._dbs = DATABASES
+        else:
+            self._dbs = {}
+        if db not in self._dbs:
+            self._dbs[db] = _ExpiringDict()
+        self._db = self._dbs[db]
         self._db_num = db
         self._encoding = charset
         self._encoding_errors = errors
@@ -282,12 +286,12 @@ def __init__(self, db=0, charset='utf-8', errors='strict',
             _patch_responses(self)
 
     def flushdb(self):
-        DATABASES[self._db_num].clear()
+        self._db.clear()
         return True
 
     def flushall(self):
-        for db in DATABASES:
-            DATABASES[db].clear()
+        for db in self._dbs.values():
+            db.clear()
 
         del self._pubsubs[:]
 

test_fakenewsredis.py

@@ -3644,6 +3644,24 @@ def test_can_accept_any_kwargs(self):
         fakenewsredis.FakeRedis(foo='bar', bar='baz')
         fakenewsredis.FakeStrictRedis(foo='bar', bar='baz')
 
+    def test_singleton(self):
+        r1 = fakenewsredis.FakeStrictRedis(singleton=False)
+        r2 = fakenewsredis.FakeStrictRedis(singleton=False)
+        r3 = fakenewsredis.FakeStrictRedis()
+        r4 = fakenewsredis.FakeStrictRedis()
+        r3.flushall()
+
+        r1.set('foo', 'bar')
+        r3.set('bar', 'baz')
+
+        self.assertIn('foo', r1)
+        self.assertNotIn('foo', r2)
+        self.assertNotIn('foo', r3)
+
+        self.assertIn('bar', r3)
+        self.assertIn('bar', r4)
+        self.assertNotIn('bar', r1)
+
     def test_from_url(self):
         db = fakenewsredis.FakeStrictRedis.from_url(
             'redis://username:password@localhost:6379/0')