public async Task ItAddsTheUserToAnExistingGamingGroupIfThereIsAnInvitation()
{
await userRegisterer.RegisterUser(newUser);
gamingGroupInviteConsumerMock.AssertWasCalled(mock => mock.AddNewUserToGamingGroup(
Arg<string>.Is.Equal(applicationUserIdAfterSaving),
Arg<Guid>.Is.Equal(newUser.GamingGroupInvitationId.Value)));
}