Added mailboxes as local data sources (#1022)

app/Tests/Tools/Mail/MailFolderSelectionTests.cs

@@ -0,0 +1,99 @@
+using AIStudio.Tools.Mail;
+
+namespace AIStudio.Tests.Tools.Mail;
+
+/// <summary>
+/// Checks which folders of a mailbox the sync works through.
+/// </summary>
+[TestFixture]
+public sealed class MailFolderSelectionTests
+{
+    private static readonly IReadOnlyList<MailServerFolder> SERVER_FOLDERS =
+    [
+        Folder("Archive", MailFolderSpecialUse.ARCHIVE),
+        Folder("Junk", MailFolderSpecialUse.JUNK),
+        Folder("Projects"),
+        Folder("Projects/Alpha"),
+        Folder("Projects/Alpha/Drafts of the board"),
+        Folder("ProjectsOld"),
+        Folder("Sent", MailFolderSpecialUse.SENT),
+        Folder("Starred", MailFolderSpecialUse.FLAGGED),
+        Folder("Trash", MailFolderSpecialUse.TRASH),
+        Folder("[Gmail]", canSelect: false),
+        Folder("[Gmail]/All Mail", MailFolderSpecialUse.ALL),
+        Folder("[Gmail]/Important", MailFolderSpecialUse.IMPORTANT),
+        Folder("INBOX", isInbox: true),
+        Folder("INBOX/Invoices"),
+    ];
+
+    [Test]
+    public void TheWholeMailboxLeavesOutWhatWasThrownAway()
+    {
+        var selection = MailFolderSelection.Select(SERVER_FOLDERS, string.Empty);
+        Assert.Multiple(() =>
+        {
+            Assert.That(selection.RootFolderFound, Is.True);
+            Assert.That(selection.Folders.Select(folder => folder.FullName), Is.EqualTo(new[]
+            {
+                "INBOX",
+                "Archive",
+                "INBOX/Invoices",
+                "Projects",
+                "Projects/Alpha",
+                "Projects/Alpha/Drafts of the board",
+                "ProjectsOld",
+                "Sent",
+                "[Gmail]/All Mail",
+            }), "The inbox comes first; the trash, the junk folder, the virtual folders and the grouping folder stay out.");
+        });
+    }
+
+    [Test]
+    public void ARootFolderTakesItsSubfoldersAlongAndNothingElse() =>
+        Assert.That(MailFolderSelection.Select(SERVER_FOLDERS, "Projects").Folders.Select(folder => folder.FullName), Is.EqualTo(new[] { "Projects", "Projects/Alpha", "Projects/Alpha/Drafts of the board" }), "A folder merely starting with the same name got in.");
+
+    [Test]
+    public void TheInboxIsMatchedWhateverItsCase() =>
+        Assert.That(MailFolderSelection.Select(SERVER_FOLDERS, "inbox").Folders.Select(folder => folder.FullName), Is.EqualTo(new[] { "INBOX", "INBOX/Invoices" }));
+
+    [Test]
+    public void AVirtualFolderCountsWhenItIsTheRootFolder() =>
+        Assert.That(MailFolderSelection.Select(SERVER_FOLDERS, "Starred").Folders.Select(folder => folder.FullName), Is.EqualTo(new[] { "Starred" }));
+
+    [Test]
+    public void TheTrashNeverCountsNotEvenAsRootFolder()
+    {
+        var selection = MailFolderSelection.Select(SERVER_FOLDERS, "Trash");
+        Assert.Multiple(() =>
+        {
+            Assert.That(selection.Folders, Is.Empty);
+            Assert.That(selection.RootFolderFound, Is.True);
+        });
+    }
+
+    [Test]
+    public void ARootFolderTheServerNoLongerListsIsReported()
+    {
+        var selection = MailFolderSelection.Select(SERVER_FOLDERS, "Projects/Beta");
+        Assert.Multiple(() =>
+        {
+            Assert.That(selection.RootFolderFound, Is.False, "A renamed root folder would read as a mailbox which became empty.");
+            Assert.That(selection.Folders, Is.Empty);
+        });
+    }
+
+    [Test]
+    public void AServerWithoutHierarchyHasNoSubfolders()
+    {
+        IReadOnlyList<MailServerFolder> flatFolders = [Folder("Projects", separator: '\0'), Folder("Projects.Alpha", separator: '\0')];
+        Assert.That(MailFolderSelection.Select(flatFolders, "Projects").Folders.Select(folder => folder.FullName), Is.EqualTo(new[] { "Projects" }));
+    }
+
+    private static MailServerFolder Folder(string fullName, MailFolderSpecialUse specialUse = MailFolderSpecialUse.NONE, bool isInbox = false, bool canSelect = true, char separator = '/')
+    {
+        var separatorIndex = separator is '\0' ? -1 : fullName.LastIndexOf(separator);
+        var parentFullName = separatorIndex < 0 ? string.Empty : fullName[..separatorIndex];
+        var name = separatorIndex < 0 ? fullName : fullName[(separatorIndex + 1)..];
+        return new(fullName, name, parentFullName, separator, specialUse, isInbox, canSelect);
+    }
+}