Added mailboxes as local data sources (#1022)

app/Tests/Tools/Mail/MailboxProviderTemplatesTests.cs

@@ -0,0 +1,75 @@
+using AIStudio.Settings.DataModel;
+using AIStudio.Tools.Mail;
+
+namespace AIStudio.Tests.Tools.Mail;
+
+/// <summary>
+/// Checks that every provider template would make a mailbox the connector accepts.
+/// </summary>
+/// <remarks>
+/// The table is typed in by hand. A host with a stray scheme or a port out of range would only
+/// show itself once somebody picks that provider, and then as a failed connection the user cannot
+/// explain.
+/// </remarks>
+[TestFixture]
+public sealed class MailboxProviderTemplatesTests
+{
+    private static IEnumerable<TestCaseData> Templates() => MailboxProviderTemplates.ALL.Select(template => new TestCaseData(template).SetArgDisplayNames(template.Name));
+
+    [TestCaseSource(nameof(Templates))]
+    public void ATemplateMakesAValidConnection(MailboxProviderTemplate template)
+    {
+        Assert.Multiple(() =>
+        {
+            Assert.That(template.Port, Is.InRange(1, 65535), "The port is out of range.");
+            Assert.That(template.TransportSecurity, Is.Not.EqualTo(MailboxTransportSecurity.UNKNOWN), "The template does not say how the connection is encrypted.");
+            Assert.That(Uri.TryCreate(template.HelpUrl, UriKind.Absolute, out var helpUrl) && helpUrl.Scheme == Uri.UriSchemeHttps, Is.True, "The help page is no HTTPS address.");
+        });
+    }
+
+    [TestCaseSource(nameof(Templates))]
+    public void ATemplateNamesAHostUnlessEveryOrganizationRunsItsOwn(MailboxProviderTemplate template)
+    {
+        if (template.Requirements.HasFlag(MailboxProviderRequirements.ADMIN_ACTIVATION))
+            Assert.That(template.Host, Is.Empty, "A server every organization runs itself has no host to fill in.");
+        else
+            Assert.That(Uri.CheckHostName(template.Host), Is.EqualTo(UriHostNameType.Dns), "The host is no DNS name.");
+    }
+
+    [Test]
+    public void EveryProviderIsListedOnce()
+    {
+        Assert.Multiple(() =>
+        {
+            Assert.That(MailboxProviderTemplates.ALL.Select(template => template.Name), Is.Unique);
+            Assert.That(MailboxProviderTemplates.ALL.Where(template => template.Host.Length > 0).Select(template => template.Host), Is.Unique);
+        });
+    }
+
+    [Test]
+    public void EveryRequirementHasItsOwnDescription()
+    {
+        var requirements = Enum.GetValues<MailboxProviderRequirements>().Where(requirement => requirement is not MailboxProviderRequirements.NONE).ToList();
+        var descriptions = requirements.Select(requirement => requirement.GetDescriptions().ToList()).ToList();
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(MailboxProviderRequirements.NONE.GetDescriptions(), Is.Empty, "A provider without requirements got a description.");
+            Assert.That(descriptions, Has.All.Count.EqualTo(1), "A requirement does not have exactly one description.");
+            Assert.That(descriptions.Select(texts => texts.FirstOrDefault()), Is.Unique, "Two requirements share a description.");
+        });
+    }
+
+    [Test]
+    public void EveryUsernameFormatHasItsOwnDescription()
+    {
+        var descriptions = Enum.GetValues<MailboxUsernameFormat>().Select(format => format.GetDescription()).ToList();
+        var fallback = ((MailboxUsernameFormat)int.MaxValue).GetDescription();
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(descriptions, Is.Unique, "Two username formats share a description.");
+            Assert.That(descriptions, Has.None.EqualTo(fallback), "A username format falls back to the description of an unknown one.");
+        });
+    }
+}