public async Task accepts_role(UserRoleEnum role)
        {
            var sut = new ChangeUserRoleValidator();

            var result = await sut.ValidateAsync(
                new ChangeUserRoleRequest
            {
                UserId = 1,
                Role   = role
            }
                );

            result.IsValid.Should().BeTrue();
        }
        public async Task fails_on_role(UserRoleEnum role)
        {
            var sut = new ChangeUserRoleValidator();

            var result = await sut.ValidateAsync(
                new ChangeUserRoleRequest
            {
                UserId = 1,
                Role   = role
            }
                );

            result.IsValid.Should().BeFalse();
            result.Errors.Should().Contain(x => x.PropertyName == nameof(ChangeUserRoleRequest.Role));
        }