Implement a fake SDL database backend

Implement a fake SDL database backend what can be used only for
local testing purposes, when SDL client does not need real DBAAS
database services. An SDL client can activate fake SDL database
backend usage when SDL instance is initiated with optional
'fake_db_backend' parameter:
  sdl_instance = SyncStorage(fake_db_backend='dict')
Value 'dict' is only supported.

Change-Id: I2ee7474175d0923617e026c306ec684b117dab60
Signed-off-by: Timo Tietavainen <timo.tietavainen@nokia.com>
diff --git a/ricsdl-package/examples/sync.py b/ricsdl-package/examples/sync.py
index 24c8fe8..f01369a 100644
--- a/ricsdl-package/examples/sync.py
+++ b/ricsdl-package/examples/sync.py
@@ -73,6 +73,11 @@
 # Creates SDL instance. The call creates connection to the SDL database backend.
 mysdl = _try_func_return(SyncStorage)
 
+# Creates SDL instance what utilizes a fake database backend. Fake database is meant to
+# be used only at development phase of SDL clients. It does not provide more advanced
+# database services.
+# mysdl = _try_func_return(lambda: SyncStorage(fake_db_backend='dict'))
+
 
 # Sets a value 'my_value' for a key 'my_key' under given namespace. Note that value
 # type must be bytes and multiple key values can be set in one set function call.
diff --git a/ricsdl-package/ricsdl/__init__.py b/ricsdl-package/ricsdl/__init__.py
index 7fd7dd6..b527b88 100644
--- a/ricsdl-package/ricsdl/__init__.py
+++ b/ricsdl-package/ricsdl/__init__.py
@@ -31,7 +31,7 @@
 )
 
 
-__version__ = '2.0.0'
+__version__ = '2.0.1'
 
 
 __all__ = [
diff --git a/ricsdl-package/ricsdl/backend/__init__.py b/ricsdl-package/ricsdl/backend/__init__.py
index 9f25a03..a2f0eeb 100644
--- a/ricsdl-package/ricsdl/backend/__init__.py
+++ b/ricsdl-package/ricsdl/backend/__init__.py
@@ -22,15 +22,19 @@
 """Shared Data Layer (SDL) database backend module."""
 
 from importlib import import_module
+from ricsdl.configuration import DbBackendType
 
 
 def get_backend_instance(configuration):
     """
     Select database backend solution and return and instance of it.
-    For now only Redis backend solution is supported.
     """
-    backend_name = 'RedisBackend'
-    backend_module_name = 'redis'
+    if configuration.get_params().db_type == DbBackendType.FAKE_DICT:
+        backend_name = 'FakeDictBackend'
+        backend_module_name = 'fake_dict_db'
+    else:
+        backend_name = 'RedisBackend'
+        backend_module_name = 'redis'
 
     package = __package__ or __name__
     backend_module = import_module('.' + backend_module_name, package=package)
@@ -39,13 +43,16 @@
     return instance
 
 
-def get_backend_lock_instance(ns, name, expiration, backend):
+def get_backend_lock_instance(configuration, ns, name, expiration, backend):
     """
     Select database backend lock solution and return and instance of it.
-    For now only Redis backend lock solution is supported.
     """
-    backend_lock_name = 'RedisBackendLock'
-    backend_module_name = 'redis'
+    if configuration.get_params().db_type == DbBackendType.FAKE_DICT:
+        backend_lock_name = 'FakeDictBackendLock'
+        backend_module_name = 'fake_dict_db'
+    else:
+        backend_lock_name = 'RedisBackendLock'
+        backend_module_name = 'redis'
 
     package = __package__ or __name__
     backend_module = import_module('.' + backend_module_name, package=package)
diff --git a/ricsdl-package/ricsdl/backend/fake_dict_db.py b/ricsdl-package/ricsdl/backend/fake_dict_db.py
new file mode 100644
index 0000000..76e4dd9
--- /dev/null
+++ b/ricsdl-package/ricsdl/backend/fake_dict_db.py
@@ -0,0 +1,192 @@
+# Copyright (c) 2019 AT&T Intellectual Property.
+# Copyright (c) 2018-2019 Nokia.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+#
+# This source code is part of the near-RT RIC (RAN Intelligent Controller)
+# platform project (RICP).
+#
+
+
+"""The module provides fake implementation of Shared Data Layer (SDL) database backend interface."""
+import fnmatch
+from typing import (Dict, Set, List, Union)
+from ricsdl.configuration import _Configuration
+from .dbbackend_abc import DbBackendAbc
+from .dbbackend_abc import DbBackendLockAbc
+
+
+class FakeDictBackend(DbBackendAbc):
+    """
+    A class providing fake implementation of database backend of Shared Data Layer (SDL).
+    This class does not provide working database solution, this class can be used in testing
+    purposes only. Implementation does not provide shared database resource, SDL client sees
+    only its local local 'fake' database, which is a simple Python dictionary. Also keys are
+    stored in database under the same namespace.
+
+    Args:
+        configuration (_Configuration): SDL configuration, containing credentials to connect to
+                                        Redis database backend.
+    """
+    def __init__(self, configuration: _Configuration) -> None:
+        super().__init__()
+        self._db = {}
+        self._configuration = configuration
+
+    def __str__(self):
+        return str(
+            {
+                "DB type": "FAKE DB",
+            }
+        )
+
+    def close(self):
+        pass
+
+    def set(self, ns: str, data_map: Dict[str, bytes]) -> None:
+        self._db = data_map.copy()
+
+    def set_if(self, ns: str, key: str, old_data: bytes, new_data: bytes) -> bool:
+        if key not in self._db:
+            return False
+        db_data = self._db[key]
+        if db_data == old_data:
+            self._db[key] = new_data
+            return True
+        return False
+
+    def set_if_not_exists(self, ns: str, key: str, data: bytes) -> bool:
+        if key not in self._db:
+            self._db[key] = data
+            return True
+        return False
+
+    def get(self, ns: str, keys: List[str]) -> Dict[str, bytes]:
+        ret = {}
+        for k in keys:
+            if k in self._db:
+                ret[k] = self._db[k]
+        return ret
+
+    def find_keys(self, ns: str, key_pattern: str) -> List[str]:
+        ret = []
+        for k in self._db:
+            if fnmatch.fnmatch(k, key_pattern):
+                ret.append(k)
+        return ret
+
+    def find_and_get(self, ns: str, key_pattern: str) -> Dict[str, bytes]:
+        ret = {}
+        for key, val in self._db.items():
+            if fnmatch.fnmatch(key, key_pattern):
+                ret[key] = val
+        return ret
+
+    def remove(self, ns: str, keys: List[str]) -> None:
+        for key in keys:
+            self._db.pop(key, None)
+
+    def remove_if(self, ns: str, key: str, data: bytes) -> bool:
+        if key in self._db:
+            db_data = self._db[key]
+            if db_data == data:
+                self._db.pop(key)
+                return True
+        return False
+
+    def add_member(self, ns: str, group: str, members: Set[bytes]) -> None:
+        if group in self._db:
+            self._db[group] = self._db[group] | members.copy()
+        else:
+            self._db[group] = members.copy()
+
+    def remove_member(self, ns: str, group: str, members: Set[bytes]) -> None:
+        if group not in self._db:
+            return
+        for member in members:
+            self._db[group].discard(member)
+
+    def remove_group(self, ns: str, group: str) -> None:
+        self._db.pop(group, None)
+
+    def get_members(self, ns: str, group: str) -> Set[bytes]:
+        return self._db.get(group, set())
+
+    def is_member(self, ns: str, group: str, member: bytes) -> bool:
+        if group not in self._db:
+            return False
+        if member in self._db[group]:
+            return True
+        return False
+
+    def group_size(self, ns: str, group: str) -> int:
+        if group not in self._db:
+            return 0
+        return len(self._db[group])
+
+
+class FakeDictBackendLock(DbBackendLockAbc):
+    """
+    A class providing fake implementation of database backend lock of Shared Data Layer (SDL).
+    This class does not provide working database solution, this class can be used in testing
+    purposes only. Implementation does not provide shared database resource, SDL client sees
+    only its local local 'fake' database, which is a simple Python dictionary. Also keys are
+    stored in database under the same namespace.
+    Args:
+        ns (str): Namespace under which this lock is targeted.
+        name (str): Lock name, identifies the lock key in a Redis database backend.
+        expiration (int, float): Lock expiration time after which the lock is removed if it hasn't
+                                 been released earlier by a 'release' method.
+        redis_backend (FakeBackend): Database backend object containing fake databese connection.
+    """
+
+    def __init__(self, ns: str, name: str, expiration: Union[int, float],
+                 redis_backend: FakeDictBackend) -> None:
+        super().__init__(ns, name)
+        self._locked = False
+        self._ns = ns
+        self._lock_name = name
+        self._lock_expiration = expiration
+        self.redis_backend = redis_backend
+
+    def __str__(self):
+        return str(
+            {
+                "lock DB type": "FAKE DB",
+                "lock namespace": self._ns,
+                "lock name": self._lock_name,
+                "lock status": self._lock_status_to_string()
+            }
+        )
+
+    def acquire(self, retry_interval: Union[int, float] = 0.1,
+                retry_timeout: Union[int, float] = 10) -> bool:
+        if self._locked:
+            return False
+        self._locked = True
+        return self._locked
+
+    def release(self) -> None:
+        self._locked = False
+
+    def refresh(self) -> None:
+        pass
+
+    def get_validity_time(self) -> Union[int, float]:
+        return self._lock_expiration
+
+    def _lock_status_to_string(self) -> str:
+        if self._locked:
+            return 'locked'
+        return 'unlocked'
diff --git a/ricsdl-package/ricsdl/backend/redis.py b/ricsdl-package/ricsdl/backend/redis.py
index 319469e..63972e3 100644
--- a/ricsdl-package/ricsdl/backend/redis.py
+++ b/ricsdl-package/ricsdl/backend/redis.py
@@ -85,6 +85,7 @@
     def __str__(self):
         return str(
             {
+                "DB type": "Redis",
                 "Redis connection": repr(self.__redis)
             }
         )
@@ -252,6 +253,7 @@
     def __str__(self):
         return str(
             {
+                "lock DB type": "Redis",
                 "lock namespace": self._ns,
                 "lock name": self._lock_name,
                 "lock status": self._lock_status_to_string()
diff --git a/ricsdl-package/ricsdl/configuration.py b/ricsdl-package/ricsdl/configuration.py
index 91bcd98..892d607 100644
--- a/ricsdl-package/ricsdl/configuration.py
+++ b/ricsdl-package/ricsdl/configuration.py
@@ -21,16 +21,23 @@
 
 """The module provides implementation of Shared Data Layer (SDL) configurability."""
 import os
+from enum import Enum
 from collections import namedtuple
 
 
+class DbBackendType(Enum):
+    """Enumeration class of supported SDL database backend types."""
+    REDIS = 1
+    FAKE_DICT = 2
+
+
 class _Configuration():
     """This class implements Shared Data Layer (SDL) configurability."""
     Params = namedtuple('Params', ['db_host', 'db_port', 'db_sentinel_port',
-                                   'db_sentinel_master_name'])
+                                   'db_sentinel_master_name', 'db_type'])
 
-    def __init__(self):
-        self.params = self._read_configuration()
+    def __init__(self, fake_db_backend):
+        self.params = self._read_configuration(fake_db_backend)
 
     def __str__(self):
         return str(
@@ -38,7 +45,8 @@
                 "DB host": self.params.db_host,
                 "DB port": self.params.db_port,
                 "DB master sentinel": self.params.db_sentinel_master_name,
-                "DB sentinel port": self.params.db_sentinel_port
+                "DB sentinel port": self.params.db_sentinel_port,
+                "DB type": self.params.db_type.name,
             }
         )
 
@@ -47,8 +55,21 @@
         return self.params
 
     @classmethod
-    def _read_configuration(cls):
+    def _read_configuration(cls, fake_db_backend):
+        backend_type = DbBackendType.REDIS
+        if fake_db_backend:
+            if fake_db_backend.lower() != 'dict':
+                msg = ("Configuration error: "
+                       "SDL instance was initiated with wrong "
+                       "'fake_db_backend' argument value: {}. "
+                       "Value 'dict' is only supported.".
+                       format(fake_db_backend))
+                raise ValueError(msg)
+
+            backend_type = DbBackendType.FAKE_DICT
+
         return _Configuration.Params(db_host=os.getenv('DBAAS_SERVICE_HOST'),
                                      db_port=os.getenv('DBAAS_SERVICE_PORT'),
                                      db_sentinel_port=os.getenv('DBAAS_SERVICE_SENTINEL_PORT'),
-                                     db_sentinel_master_name=os.getenv('DBAAS_MASTER_NAME'))
+                                     db_sentinel_master_name=os.getenv('DBAAS_MASTER_NAME'),
+                                     db_type=backend_type)
diff --git a/ricsdl-package/ricsdl/syncstorage.py b/ricsdl-package/ricsdl/syncstorage.py
index cec5761..41deeba 100644
--- a/ricsdl-package/ricsdl/syncstorage.py
+++ b/ricsdl-package/ricsdl/syncstorage.py
@@ -69,7 +69,9 @@
                  storage: 'SyncStorage') -> None:
 
         super().__init__(ns, name, expiration)
-        self.__dbbackendlock = ricsdl.backend.get_backend_lock_instance(ns, name, expiration,
+        self.__configuration = storage.get_configuration()
+        self.__dbbackendlock = ricsdl.backend.get_backend_lock_instance(self.__configuration,
+                                                                        ns, name, expiration,
                                                                         storage.get_backend())
 
     def __str__(self):
@@ -107,11 +109,16 @@
     a namespace, namespace identifier is passed as a parameter to all the operations.
 
     Args:
-        None
+        fake_db_backend (str): Optional parameter. Parameter enables fake DB backend usage for an
+                               SDL instance. Fake DB backend is ONLY allowed to use for testing
+                               purposes at development phase of SDL clients when more advanced
+                               database services are not necessarily needed. Currently value 'dict'
+                               is only allowed value for the parameter, which enables dictionary
+                               type of fake DB backend.
     """
-    def __init__(self) -> None:
+    def __init__(self, fake_db_backend=None) -> None:
         super().__init__()
-        self.__configuration = _Configuration()
+        self.__configuration = _Configuration(fake_db_backend)
         self.__dbbackend = ricsdl.backend.get_backend_instance(self.__configuration)
 
     def __del__(self):
@@ -199,3 +206,7 @@
     def get_backend(self) -> DbBackendAbc:
         """Return backend instance."""
         return self.__dbbackend
+
+    def get_configuration(self) -> _Configuration:
+        """Return configuration what was valid when the SDL instance was initiated."""
+        return self.__configuration
diff --git a/ricsdl-package/tests/backend/test_fake_dict_db.py b/ricsdl-package/tests/backend/test_fake_dict_db.py
new file mode 100644
index 0000000..835514c
--- /dev/null
+++ b/ricsdl-package/tests/backend/test_fake_dict_db.py
@@ -0,0 +1,215 @@
+# Copyright (c) 2019 AT&T Intellectual Property.
+# Copyright (c) 2018-2019 Nokia.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+#
+# This source code is part of the near-RT RIC (RAN Intelligent Controller)
+# platform project (RICP).
+#
+
+
+from unittest.mock import Mock
+import pytest
+import ricsdl.backend
+from ricsdl.configuration import _Configuration
+from ricsdl.configuration import DbBackendType
+
+
+@pytest.fixture()
+def fake_dict_backend_fixture(request):
+    request.cls.ns = 'some-ns'
+    request.cls.dm = {'abc': b'1', 'bcd': b'2'}
+    request.cls.new_dm = {'abc': b'3', 'bcd': b'2'}
+    request.cls.remove_dm = {'bcd': b'2'}
+    request.cls.key = 'abc'
+    request.cls.keys = ['abc', 'bcd']
+    request.cls.old_data = b'1'
+    request.cls.new_data = b'3'
+    request.cls.keypattern = r'*bc*'
+    request.cls.group = 'some-group'
+    request.cls.groupmember = b'm1'
+    request.cls.groupmembers = set([b'm1', b'm2'])
+    request.cls.new_groupmembers = set(b'm3')
+    request.cls.all_groupmembers = request.cls.groupmembers | request.cls.new_groupmembers
+
+    request.cls.configuration = Mock()
+    mock_conf_params = _Configuration.Params(db_host=None,
+                                             db_port=None,
+                                             db_sentinel_port=None,
+                                             db_sentinel_master_name=None,
+                                             db_type=DbBackendType.FAKE_DICT)
+    request.cls.configuration.get_params.return_value = mock_conf_params
+    request.cls.db = ricsdl.backend.get_backend_instance(request.cls.configuration)
+
+
+@pytest.mark.usefixtures('fake_dict_backend_fixture')
+class TestFakeDictBackend:
+    def test_set_function_success(self):
+        self.db.set(self.ns, self.dm)
+        ret = self.db.get(self.ns, self.keys)
+        assert ret == self.dm
+
+    def test_set_if_function_success(self):
+        self.db.set(self.ns, self.dm)
+        ret = self.db.set_if(self.ns, self.key, self.old_data, self.new_data)
+        assert ret is True
+        ret = self.db.get(self.ns, self.keys)
+        assert ret == self.new_dm
+
+    def test_set_if_function_returns_false_if_existing_key_value_not_expected(self):
+        self.db.set_if(self.ns, self.key, self.old_data, self.new_data)
+        self.db.set(self.ns, self.new_dm)
+        ret = self.db.set_if(self.ns, self.key, self.old_data, self.new_data)
+        assert ret is False
+
+    def test_set_if_not_exists_function_success(self):
+        ret = self.db.set_if_not_exists(self.ns, self.key, self.new_data)
+        assert ret is True
+        ret = self.db.get(self.ns, self.keys)
+        assert ret == {self.key: self.new_data}
+
+    def test_set_if_not_exists_function_returns_false_if_key_already_exists(self):
+        self.db.set(self.ns, self.dm)
+        ret = self.db.set_if_not_exists(self.ns, self.key, self.new_data)
+        assert ret is False
+
+    def test_find_keys_function_success(self):
+        self.db.set(self.ns, self.dm)
+        ret = self.db.find_keys(self.ns, self.keypattern)
+        assert ret == self.keys
+
+    def test_find_keys_function_returns_empty_list_when_no_matching_keys_found(self):
+        ret = self.db.find_keys(self.ns, self.keypattern)
+        assert ret == []
+
+    def test_find_and_get_function_success(self):
+        self.db.set(self.ns, self.dm)
+        ret = self.db.find_and_get(self.ns, self.keypattern)
+        assert ret == self.dm
+
+    def test_find_and_get_function_returns_empty_dict_when_no_matching_keys_exist(self):
+        ret = self.db.find_and_get(self.ns, self.keypattern)
+        assert ret == dict()
+
+    def test_remove_function_success(self):
+        self.db.set(self.ns, self.dm)
+        self.db.remove(self.ns, self.keys)
+        ret = self.db.get(self.ns, self.keys)
+        assert ret == dict()
+
+    def test_remove_if_function_success(self):
+        self.db.set(self.ns, self.dm)
+        ret = self.db.remove_if(self.ns, self.key, self.old_data)
+        assert ret is True
+        ret = self.db.get(self.ns, self.keys)
+        assert ret == self.remove_dm
+
+    def test_remove_if_function_returns_false_if_data_does_not_match(self):
+        ret = self.db.remove_if(self.ns, self.key, self.old_data)
+        assert ret is False
+        self.db.set(self.ns, self.dm)
+        ret = self.db.remove_if(self.ns, self.key, self.new_data)
+        assert ret is False
+
+    def test_add_member_function_success(self):
+        self.db.add_member(self.ns, self.group, self.groupmembers)
+        ret = self.db.get_members(self.ns, self.group)
+        assert ret == self.groupmembers
+
+        self.db.add_member(self.ns, self.group, self.new_groupmembers)
+        ret = self.db.get_members(self.ns, self.group)
+        assert ret == self.all_groupmembers
+
+    def test_remove_member_function_success(self):
+        self.db.remove_member(self.ns, self.group, self.groupmembers)
+        self.db.add_member(self.ns, self.group, self.groupmembers)
+        self.db.remove_member(self.ns, self.group, self.groupmembers)
+        ret = self.db.get_members(self.ns, self.group)
+        assert ret == set()
+
+    def test_remove_group_function_success(self):
+        self.db.remove_group(self.ns, self.group)
+        ret = self.db.get_members(self.ns, self.group)
+        assert ret == set()
+
+    def test_is_member_function_success(self):
+        ret = self.db.is_member(self.ns, self.group, b'not member')
+        assert ret is False
+        self.db.add_member(self.ns, self.group, self.groupmembers)
+        ret = self.db.is_member(self.ns, self.group, self.groupmember)
+        assert ret is True
+        ret = self.db.is_member(self.ns, self.group, b'not member')
+        assert ret is False
+
+    def test_group_size_function_success(self):
+        ret = self.db.group_size(self.ns, self.group)
+        assert ret == 0
+        self.db.add_member(self.ns, self.group, self.groupmembers)
+        ret = self.db.group_size(self.ns, self.group)
+        assert ret == len(self.groupmembers)
+
+    def test_fake_dict_backend_object_string_representation(self):
+        assert str(self.db) == str({'DB type': 'FAKE DB'})
+
+@pytest.fixture()
+def fake_dict_backend_lock_fixture(request):
+    request.cls.ns = 'some-ns'
+    request.cls.lockname = 'some-lock-name'
+    request.cls.expiration = 10
+    request.cls.retry_interval = 0.1
+    request.cls.retry_timeout = 1
+
+    request.cls.configuration = Mock()
+    mock_conf_params = _Configuration.Params(db_host=None,
+                                             db_port=None,
+                                             db_sentinel_port=None,
+                                             db_sentinel_master_name=None,
+                                             db_type=DbBackendType.FAKE_DICT)
+    request.cls.configuration.get_params.return_value = mock_conf_params
+    request.cls.lock = ricsdl.backend.get_backend_lock_instance(request.cls.configuration,
+                                                                request.cls.ns,
+                                                                request.cls.lockname,
+                                                                request.cls.expiration,
+                                                                Mock())
+
+
+@pytest.mark.usefixtures('fake_dict_backend_lock_fixture')
+class TestFakeDictBackendLock:
+    def test_acquire_function_success(self):
+        ret = self.lock.acquire(self.retry_interval, self.retry_timeout)
+        assert ret is True
+
+    def test_acquire_function_returns_false_if_lock_is_not_acquired(self):
+        self.lock.acquire(self.retry_interval, self.retry_timeout)
+        ret = self.lock.acquire(self.retry_interval, self.retry_timeout)
+        assert ret is False
+
+    def test_release_function_success(self):
+        self.lock.acquire(self.retry_interval, self.retry_timeout)
+        ret = self.lock.acquire(self.retry_interval, self.retry_timeout)
+        assert ret is False
+        self.lock.release()
+        ret = self.lock.acquire(self.retry_interval, self.retry_timeout)
+        assert ret is True
+
+    def test_get_validity_time_function_success(self):
+        ret = self.lock.get_validity_time()
+        assert ret == self.expiration
+
+    def test_fake_dict_backend_lock_object_string_representation(self):
+        expected_lock_info = {'lock DB type': 'FAKE DB',
+                              'lock namespace': 'some-ns',
+                              'lock name': 'some-lock-name',
+                              'lock status': 'unlocked'}
+        assert str(self.lock) == str(expected_lock_info)
diff --git a/ricsdl-package/tests/backend/test_redis.py b/ricsdl-package/tests/backend/test_redis.py
index 72d7c02..61b56ff 100644
--- a/ricsdl-package/tests/backend/test_redis.py
+++ b/ricsdl-package/tests/backend/test_redis.py
@@ -25,6 +25,7 @@
 import ricsdl.backend
 from ricsdl.backend.redis import (RedisBackendLock, _map_to_sdl_exception)
 from ricsdl.configuration import _Configuration
+from ricsdl.configuration import DbBackendType
 import ricsdl.exceptions
 
 
@@ -58,7 +59,8 @@
     mock_conf_params = _Configuration.Params(db_host=None,
                                              db_port=None,
                                              db_sentinel_port=None,
-                                             db_sentinel_master_name=None)
+                                             db_sentinel_master_name=None,
+                                             db_type=DbBackendType.REDIS)
     request.cls.configuration.get_params.return_value = mock_conf_params
     with patch('ricsdl.backend.redis.Redis') as mock_redis:
         db = ricsdl.backend.get_backend_instance(request.cls.configuration)
@@ -86,7 +88,7 @@
                                                                 self.new_data, self.old_data)
         assert ret is True
 
-    def test_set_if_function_returns_false_if_same_data_already_exists(self):
+    def test_set_if_function_returns_false_if_existing_key_value_not_expected(self):
         self.mock_redis.execute_command.return_value = False
         ret = self.db.set_if(self.ns, self.key, self.old_data, self.new_data)
         self.mock_redis.execute_command.assert_called_once_with('SETIE', self.key_redis,
@@ -346,8 +348,18 @@
 
     mocked_dbbackend = Mock()
     mocked_dbbackend.get_redis_connection.return_value = request.cls.mock_redis
+
+    request.cls.configuration = Mock()
+    mock_conf_params = _Configuration.Params(db_host=None,
+                                             db_port=None,
+                                             db_sentinel_port=None,
+                                             db_sentinel_master_name=None,
+                                             db_type=DbBackendType.REDIS)
+    request.cls.configuration.get_params.return_value = mock_conf_params
+
     with patch('ricsdl.backend.redis.Lock') as mock_redis_lock:
-        lock = ricsdl.backend.get_backend_lock_instance(request.cls.ns, request.cls.lockname,
+        lock = ricsdl.backend.get_backend_lock_instance(request.cls.configuration,
+                                                        request.cls.ns, request.cls.lockname,
                                                         request.cls.expiration, mocked_dbbackend)
         request.cls.mock_redis_lock = mock_redis_lock.return_value
         request.cls.lock = lock
@@ -358,8 +370,16 @@
 @pytest.mark.usefixtures('redis_backend_lock_fixture')
 class TestRedisBackendLock:
     def test_acquire_function_success(self):
-        self.lock.acquire(self.retry_interval, self.retry_timeout)
+        self.mock_redis_lock.acquire.return_value = True
+        ret = self.lock.acquire(self.retry_interval, self.retry_timeout)
         self.mock_redis_lock.acquire.assert_called_once_with(blocking_timeout=self.retry_timeout)
+        assert ret is True
+
+    def test_acquire_function_returns_false_if_lock_is_not_acquired(self):
+        self.mock_redis_lock.acquire.return_value = False
+        ret = self.lock.acquire(self.retry_interval, self.retry_timeout)
+        self.mock_redis_lock.acquire.assert_called_once_with(blocking_timeout=self.retry_timeout)
+        assert ret is False
 
     def test_acquire_function_can_map_redis_exception_to_sdl_exception(self):
         self.mock_redis_lock.acquire.side_effect = redis_exceptions.LockError('redis lock error!')
@@ -421,14 +441,16 @@
         assert f"Getting validity time of a lock {self.lockname} failed with error code: -10" in str(excinfo.value)
 
     def test_redis_backend_lock_object_string_representation(self):
-        expected_lock_info = {'lock namespace': 'some-ns',
+        expected_lock_info = {'lock DB type': 'Redis',
+                              'lock namespace': 'some-ns',
                               'lock name': 'some-lock-name',
                               'lock status': 'locked'}
         assert str(self.lock) == str(expected_lock_info)
 
     def test_redis_backend_lock_object_string_representation_can_catch_redis_exception(self):
         self.mock_redis_lock.owned.side_effect = redis_exceptions.LockError('redis lock error!')
-        expected_lock_info = {'lock namespace': 'some-ns',
+        expected_lock_info = {'lock DB type': 'Redis',
+                              'lock namespace': 'some-ns',
                               'lock name': 'some-lock-name',
                               'lock status': 'Error: redis lock error!'}
         assert str(self.lock) == str(expected_lock_info)
diff --git a/ricsdl-package/tests/test_configuration.py b/ricsdl-package/tests/test_configuration.py
index 7b17221..6905bf6 100644
--- a/ricsdl-package/tests/test_configuration.py
+++ b/ricsdl-package/tests/test_configuration.py
@@ -21,6 +21,7 @@
 
 import pytest
 from ricsdl.configuration import _Configuration
+from ricsdl.configuration import DbBackendType
 
 
 @pytest.fixture()
@@ -29,43 +30,50 @@
     monkeypatch.setenv('DBAAS_SERVICE_PORT', '10000')
     monkeypatch.setenv('DBAAS_SERVICE_SENTINEL_PORT', '11000')
     monkeypatch.setenv('DBAAS_MASTER_NAME', 'my-master')
-    request.cls.config = _Configuration()
-    request.cls.config._read_configuration()
+    request.cls.config = _Configuration(fake_db_backend=None)
 
 
 @pytest.fixture
-def config_missing_fixture(request, monkeypatch):
+def fake_db_config_fixture(request, monkeypatch):
     monkeypatch.delenv('DBAAS_SERVICE_HOST', raising=False)
     monkeypatch.delenv('DBAAS_SERVICE_PORT', raising=False)
     monkeypatch.delenv('DBAAS_SERVICE_SENTINEL_PORT', raising=False)
     monkeypatch.delenv('DBAAS_MASTER_NAME', raising=False)
-    request.cls.config = _Configuration()
-    request.cls.config._read_configuration()
+    request.cls.config = _Configuration(fake_db_backend='dict')
 
 
 class TestConfiguration:
     def test_get_params_function_returns_read_configuration(self, config_fixture):
         expected_config = _Configuration.Params(db_host='10.20.30.40', db_port='10000',
                                                 db_sentinel_port='11000',
-                                                db_sentinel_master_name='my-master')
+                                                db_sentinel_master_name='my-master',
+                                                db_type=DbBackendType.REDIS)
         assert expected_config == self.config.get_params()
 
-    def test_get_params_function_can_return_empty_configuration(self, config_missing_fixture):
+    def test_get_params_function_can_return_fake_db_configuration(self, fake_db_config_fixture):
         expected_config = _Configuration.Params(db_host=None, db_port=None,
                                                 db_sentinel_port=None,
-                                                db_sentinel_master_name=None)
+                                                db_sentinel_master_name=None,
+                                                db_type=DbBackendType.FAKE_DICT)
         assert expected_config == self.config.get_params()
 
+    def test_get_params_function_can_raise_exception_if_wrong_fake_db_type(self):
+        with pytest.raises(ValueError, match=r"Configuration error"):
+            _Configuration(fake_db_backend='bad value')
+
+
     def test_configuration_object_string_representation(self, config_fixture):
         expected_config_info = {'DB host': '10.20.30.40',
                                 'DB port': '10000',
                                 'DB master sentinel': 'my-master',
-                                'DB sentinel port': '11000'}
+                                'DB sentinel port': '11000',
+                                'DB type': 'REDIS'}
         assert str(self.config) == str(expected_config_info)
 
-    def test_configuration_object_string_representation_if_no_config(self, config_missing_fixture):
+    def test_configuration_object_string_representation_if_fake_db(self, fake_db_config_fixture):
         expected_config_info = {'DB host': None,
                                 'DB port': None,
                                 'DB master sentinel': None,
-                                'DB sentinel port': None}
+                                'DB sentinel port': None,
+                                'DB type': 'FAKE_DICT'}
         assert str(self.config) == str(expected_config_info)