public async Task OnGetAsync_GivenThereAreNoRoles_ExpectEmptyList()
        {
            var mediator    = new Mock <IMediator>();
            var roleQueries = new Mock <IRoleQueries>();

            roleQueries.Setup(x => x.GetSimpleRoles())
            .ReturnsAsync(Maybe <List <SimpleRoleModel> > .Nothing);

            var page = new CreateUser(mediator.Object, roleQueries.Object);
            await page.OnGetAsync();

            Assert.Empty(page.AvailableRoles);
        }
        public async Task OnGetAsync_GivenThereAreRoles_ExpectPopulatedList()
        {
            var mediator    = new Mock <IMediator>();
            var roleQueries = new Mock <IRoleQueries>();

            roleQueries.Setup(x => x.GetSimpleRoles())
            .ReturnsAsync(Maybe.From(new List <SimpleRoleModel>
            {
                new SimpleRoleModel(TestVariables.RoleId, "name"),
            }));

            var page = new CreateUser(mediator.Object, roleQueries.Object);
            await page.OnGetAsync();

            Assert.Single(page.AvailableRoles);
        }