Allowed the Batch Processing assistant to process images (#1087)

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

app/Tests/Settings/ImageInputSupportTests.cs

@@ -0,0 +1,63 @@
+using AIStudio.Provider;
+using AIStudio.Settings;
+
+namespace AIStudio.Tests.Settings;
+
+/// <summary>
+/// Checks whether a configured model counts as able to read images.
+/// </summary>
+/// <remarks>
+/// Attaching a file to a chat, building a request, and the Batch Processing assistant all ask this one
+/// question. A limit of zero images is a statement about the installation, so it has to win over the
+/// capability, while a limit nobody stated must not take anything away.
+/// </remarks>
+[TestFixture]
+public sealed class ImageInputSupportTests
+{
+    private const string MACHINE = "55555555-5555-5555-5555-555555555555";
+
+    /// <summary>
+    /// A model the rules know as reading text only, so that every image capability comes from the overrides.
+    /// </summary>
+    private static readonly Model MODEL = new("llama3.3:70b", null);
+
+    [Test]
+    public void AModelWithoutImageCapabilityCannotReadImages()
+    {
+        Assert.That(ProviderWith(null).SupportsImageInput(), Is.False);
+    }
+
+    [Test]
+    public void AnImageCapabilityWithoutAStatedLimitReadsImages()
+    {
+        Assert.That(ProviderWith(new() { MultipleImageInput = true }).SupportsImageInput(), Is.True, "Nobody stated a limit, and an unknown limit takes nothing away.");
+    }
+
+    [Test]
+    public void ALimitOfOneImageStillReadsImages()
+    {
+        Assert.That(ProviderWith(new() { MultipleImageInput = true, MaxImagesPerMessage = 1 }).SupportsImageInput(), Is.True);
+    }
+
+    [Test]
+    public void ALimitOfZeroImagesPerMessageTakesTheCapabilityBack()
+    {
+        Assert.That(ProviderWith(new() { MultipleImageInput = true, MaxImagesPerMessage = 0 }).SupportsImageInput(), Is.False);
+    }
+
+    [Test]
+    public void ALimitOfZeroImagesPerRequestTakesTheCapabilityBack()
+    {
+        Assert.That(ProviderWith(new() { MultipleImageInput = true, MaxImagesPerRequest = 0 }).SupportsImageInput(), Is.False, "A message cannot carry more images than its whole request.");
+    }
+
+    /// <summary>
+    /// A configured self-hosted provider, the way the settings hold one.
+    /// </summary>
+    /// <param name="overrides">What the person switched, or nothing when they switched nothing.</param>
+    /// <returns>The configured provider.</returns>
+    private static AIStudio.Settings.Provider ProviderWith(ProviderCapabilityOverrides? overrides) => new(1, MACHINE, "A machine of my own", LLMProviders.SELF_HOSTED, MODEL, IsSelfHosted: true)
+    {
+        CapabilityOverrides = overrides,
+    };
+}