public void GetAll_ReturnsAddresses_ForSpecificUser()
{
target.AddUpdate("User1", new Address { Id = "address1"});
target.AddUpdate("User2", new Address { Id = "address2"});
target.AddUpdate("User2", new Address { Id = "address3" });
Assert.AreEqual(1, target.GetAll("User1").Count());
Assert.AreEqual(2, target.GetAll("User2").Count());
}