Added PowerPoint templates to the Slide Assistant (#1055)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/Tests/Tools/PowerPoint/LayoutPurposeTests.cs

@@ -0,0 +1,52 @@
+using AIStudio.Tools.PowerPoint;
+
+namespace AIStudio.Tests.Tools.PowerPoint;
+
+/// <summary>
+/// Checks the kinds of slides the user may choose layouts for.
+/// </summary>
+[TestFixture]
+public sealed class LayoutPurposeTests
+{
+    [Test]
+    public void EveryKindOfSlideIsDescribedForTheUserAndTheModel()
+    {
+        Assert.Multiple(() =>
+        {
+            foreach (var purpose in Enum.GetValues<LayoutPurpose>())
+            {
+                Assert.That(purpose.Label(), Is.Not.Empty, $"The kind of slide {purpose} has no label.");
+                Assert.That(purpose.Question(), Does.EndWith("?"), $"The kind of slide {purpose} has no question.");
+                Assert.That(purpose.PromptDescription(), Is.Not.Empty.And.Not.EndWith("."), $"The kind of slide {purpose} has no description, or one which ends where the rule for the model goes on.");
+            }
+        });
+    }
+
+    /// <summary>
+    /// Checks that no two kinds of slides read the same, since the user tells them apart by their labels only.
+    /// </summary>
+    [Test]
+    public void EveryKindOfSlideHasALabelOfItsOwn()
+    {
+        var labels = Enum.GetValues<LayoutPurpose>().Select(purpose => purpose.Label()).ToList();
+        Assert.That(labels, Is.Unique);
+    }
+
+    /// <summary>
+    /// Checks that the kinds of slides are grouped by area, in the order of the areas.
+    /// </summary>
+    /// <remarks>
+    /// The forms list the kinds of each area together, in the order of the enum. A kind added at the
+    /// end of the enum rather than within its area would break up the areas.
+    /// </remarks>
+    [Test]
+    public void TheKindsOfSlidesFollowTheOrderOfTheAreas()
+    {
+        var areas = Enum.GetValues<LayoutPurpose>().Select(purpose => purpose.Area()).ToList();
+        Assert.Multiple(() =>
+        {
+            Assert.That(areas, Is.Ordered, "The kinds of an area stand together, and the areas follow their own order.");
+            Assert.That(areas.Distinct(), Is.EquivalentTo(Enum.GetValues<LayoutPurposeArea>()), "Every area has kinds of slides.");
+        });
+    }
+}