public async Task When_ConfirmationCode_Does_Not_Exist_Then_Null_Is_Returned() { _confirmationCodeStoreStub.Setup(c => c.Get(It.IsAny <string>(), It.IsAny <string>(), It.IsAny <CancellationToken>())) .Returns(() => Task.FromResult((ConfirmationCode)null)); var result = await _authenticateResourceOwnerService .AuthenticateResourceOwner("login", "password", CancellationToken.None) .ConfigureAwait(false); Assert.Null(result); }