diff --git a/tests/functional/pyocf/types/data.py b/tests/functional/pyocf/types/data.py
index fad4396..e65dfaf 100644
--- a/tests/functional/pyocf/types/data.py
+++ b/tests/functional/pyocf/types/data.py
@@ -59,7 +59,7 @@ class Data:
     DATA_POISON = 0xA5
     PAGE_SIZE = 4096
 
-    _instances_ = {}
+    _instances_ = weakref.WeakValueDictionary()
     _ocf_instances_ = []
 
     def __init__(self, byte_count: int):
@@ -69,12 +69,12 @@ class Data:
         self.handle = cast(byref(self.buffer), c_void_p)
 
         memset(self.handle, self.DATA_POISON, self.size)
-        type(self)._instances_[self.handle.value] = weakref.ref(self)
+        type(self)._instances_[self.handle.value] = self
         self._as_parameter_ = self.handle
 
     @classmethod
     def get_instance(cls, ref):
-        return cls._instances_[ref]()
+        return cls._instances_[ref]
 
     @classmethod
     def get_ops(cls):
diff --git a/tests/functional/pyocf/types/logger.py b/tests/functional/pyocf/types/logger.py
index 9518bb0..df7e963 100644
--- a/tests/functional/pyocf/types/logger.py
+++ b/tests/functional/pyocf/types/logger.py
@@ -69,7 +69,7 @@ class LoggerPriv(Structure):
 
 
 class Logger(Structure):
-    _instances_ = {}
+    _instances_ = weakref.WeakValueDictionary()
 
     _fields_ = [("logger", c_void_p)]
 
@@ -81,7 +81,7 @@ class Logger(Structure):
         )
         self.priv = LoggerPriv(_log=self._log)
         self._as_parameter_ = cast(pointer(self.priv), c_void_p).value
-        self._instances_[self._as_parameter_] = weakref.ref(self)
+        self._instances_[self._as_parameter_] = self
 
     def get_ops(self):
         return self.ops
@@ -92,7 +92,7 @@ class Logger(Structure):
     @classmethod
     def get_instance(cls, ctx: int):
         priv = OcfLib.getInstance().ocf_logger_get_priv(ctx)
-        return cls._instances_[priv]()
+        return cls._instances_[priv]
 
     @staticmethod
     @LoggerOps.LOG
diff --git a/tests/functional/pyocf/types/queue.py b/tests/functional/pyocf/types/queue.py
index eed3c5f..112a848 100644
--- a/tests/functional/pyocf/types/queue.py
+++ b/tests/functional/pyocf/types/queue.py
@@ -38,7 +38,7 @@ def io_queue_run(*, queue: Queue, kick: Condition, stop: Event):
 
 
 class Queue:
-    _instances_ = {}
+    _instances_ = weakref.WeakValueDictionary()
 
     def __init__(self, cache, name):
 
@@ -51,7 +51,7 @@ class Queue:
         if status:
             raise OcfError("Couldn't create queue object", status)
 
-        Queue._instances_[self.handle.value] = weakref.ref(self)
+        Queue._instances_[self.handle.value] = self
         self._as_parameter_ = self.handle
 
         self.stop_event = Event()
@@ -70,7 +70,7 @@ class Queue:
 
     @classmethod
     def get_instance(cls, ref):
-        return cls._instances_[ref]()
+        return cls._instances_[ref]
 
     @staticmethod
     @QueueOps.KICK_SYNC
diff --git a/tests/functional/pyocf/types/volume.py b/tests/functional/pyocf/types/volume.py
index 33f39e3..4fbac92 100644
--- a/tests/functional/pyocf/types/volume.py
+++ b/tests/functional/pyocf/types/volume.py
@@ -78,8 +78,8 @@ class Volume(Structure):
     VOLUME_POISON = 0x13
 
     _fields_ = [("_storage", c_void_p)]
-    _instances_ = {}
-    _uuid_ = {}
+    _instances_ = weakref.WeakValueDictionary()
+    _uuid_ = weakref.WeakValueDictionary()
 
     props = None
 
@@ -95,7 +95,7 @@ class Volume(Structure):
         else:
             self.uuid = str(id(self))
 
-        type(self)._uuid_[self.uuid] = weakref.ref(self)
+        type(self)._uuid_[self.uuid] = self
 
         self.data = create_string_buffer(int(self.size))
         memset(self.data, self.VOLUME_POISON, self.size)
@@ -138,7 +138,7 @@ class Volume(Structure):
 
     @classmethod
     def get_instance(cls, ref):
-        instance = cls._instances_[ref]()
+        instance = cls._instances_[ref]
         if instance is None:
             print("tried to access {} but it's gone".format(ref))
 
@@ -146,7 +146,7 @@ class Volume(Structure):
 
     @classmethod
     def get_by_uuid(cls, uuid):
-        return cls._uuid_[uuid]()
+        return cls._uuid_[uuid]
 
     @staticmethod
     @VolumeOps.SUBMIT_IO
@@ -205,7 +205,7 @@ class Volume(Structure):
         if volume.opened:
             return -OcfErrorCode.OCF_ERR_NOT_OPEN_EXC
 
-        Volume._instances_[ref] = weakref.ref(volume)
+        Volume._instances_[ref] = volume
 
         return volume.open()