public void CreateFriend()
        {
            // Arrange
            FriendEntity friend = new FriendEntity
            {
                Username = "******",
                IsClose  = true
            };

            // Act
            friendService.CreateFriend("alex", friend);
            FriendEntity rel = friendService.GetFriendship("alex", "test");

            // Assert
            Assert.AreNotEqual(rel, null);
        }