public static void TestSubject()
        {
            var email = new SingleAllocation(new Allocation {
                Date = 18.December(2018)
            });

            Assert.Equal("Space available on 18 Dec", email.Subject);
        }
        public static void TestTo(string to)
        {
            var email = new SingleAllocation(new Allocation {
                ApplicationUser = new ApplicationUser {
                    Email = to
                }
            });

            Assert.Equal(to, email.To);
        }
        public static void TestBody()
        {
            var email = new SingleAllocation(new Allocation {
                Date = 18.December(2018)
            });

            const string ExpectedBody = "A space has been allocated to you for 18 Dec.";

            Assert.True(email.HtmlBody.Contains(ExpectedBody, StringComparison.OrdinalIgnoreCase));
            Assert.True(email.PlainTextBody.Contains(ExpectedBody, StringComparison.OrdinalIgnoreCase));
        }