public void TestInitialize()
		{
			priceFeedGenerator = Substitute.For<IPriceFeedGenerator>();
			priceFeedSubscriber = Substitute.For<IPriceFeedSubscriber>();
			subscriptionStore = Substitute.For<ISubscriptionStore>();

			subscriptionManagerUnderTest = new GroupSubscriptionManager(priceFeedGenerator, priceFeedSubscriber, subscriptionStore);
		}
		public GroupSubscriptionManager(IPriceFeedGenerator priceFeedGenerator, IPriceFeedSubscriber priceFeedSubscriber, ISubscriptionStore subscriptionStore)
		{
			this.priceFeedGenerator = priceFeedGenerator;
			this.priceFeedSubscriber = priceFeedSubscriber;
			this.subscriptionStore = subscriptionStore;
		}