Added a way to read what the AI received from your sources (#1100)

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

app/Tests/Tools/RetrievalContextSourcesTests.cs

@@ -10,7 +10,8 @@ namespace AIStudio.Tests.Tools;
 /// The sources below an answer are links the user opens, and they travel into every export. The
 /// classic RAG process and Semantic Search both take them from here, so a passage has to name the
 /// same sources whichever of the two found it. A source has to open where the passage is, and
-/// nothing may become a link which does not lead anywhere sensible.
+/// nothing may become a link which does not lead anywhere sensible. What names nothing to open
+/// still becomes a source, named as text, since the user reads under it what the AI received.
 /// </remarks>
 [TestFixture]
 public sealed class RetrievalContextSourcesTests
@@ -48,11 +49,48 @@ public sealed class RetrievalContextSourcesTests
     }
 
     [Test]
-    public void ARelativePathBecomesNoSource()
+    public void ARelativePathBecomesASourceWithoutLink()
     {
         var sources = TextContext(path: Path.Combine("docs", "handbook.pdf")).ToSources();
 
-        Assert.That(sources, Is.Empty, "A relative path would point somewhere else depending on where it is opened from.");
+        Assert.Multiple(() =>
+        {
+            Assert.That(sources, Has.Count.EqualTo(1), "The AI received the passage, so it needs a source to be read at.");
+            Assert.That(sources[0].Title, Is.EqualTo("Handbooks"));
+            Assert.That(sources[0].HasNoLink(), Is.True, "A relative path would point somewhere else depending on where it is opened from.");
+            Assert.That(sources[0].TryGetDocumentLocation(out _), Is.False);
+        });
+    }
+
+    [Test]
+    public void APathOnlyTheDataSourceKnowsBecomesASourceWithoutLink()
+    {
+        var sources = TextContext(path: "db://collection/42").ToSources();
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(sources, Has.Count.EqualTo(1));
+            Assert.That(sources[0].HasNoLink(), Is.True, "An ERI server may name its content in a way no program here can open.");
+        });
+    }
+
+    [Test]
+    public void ThePassagesOfOneDocumentGatherUnderOneSource()
+    {
+        List<Source> sources = [..TextContext(path: "db://collection/42").ToSources()];
+
+        sources.MergeSources(TextContext(path: "db://collection/42").ToSources());
+        sources.MergeSources(TextContext(path: "db://collection/43").ToSources());
+
+        Assert.That(sources, Has.Count.EqualTo(2), "The same document is one source; another document is another.");
+    }
+
+    [Test]
+    public void AContextWithoutAnyNameGetsNoSource()
+    {
+        var context = TextContext(path: "db://collection/42", dataSourceName: string.Empty);
+
+        Assert.That(context.ToSources(), Is.Empty, "A source without a name would be an entry nobody can tell apart.");
     }
 
     [Test]
@@ -69,9 +107,9 @@ public sealed class RetrievalContextSourcesTests
 
     private static string AbsolutePath(string fileName) => Path.GetFullPath(Path.Combine(Path.GetTempPath(), fileName));
 
-    private static RetrievalTextContext TextContext(string path, string referenceTitle = "", string referenceLink = "", IReadOnlyList<string>? links = null) => new()
+    private static RetrievalTextContext TextContext(string path, string referenceTitle = "", string referenceLink = "", IReadOnlyList<string>? links = null, string dataSourceName = "Handbooks") => new()
     {
-        DataSourceName = "Handbooks",
+        DataSourceName = dataSourceName,
         Category = RetrievalContentCategory.TEXT,
         Type = RetrievalContentType.TEXT_DOCUMENT,
         Path = path,