Use MDEx streaming to render chat content

test/music_library_web/markdown_test.exs

@@ -5,6 +5,40 @@ defmodule MusicLibraryWeb.MarkdownTest do
 
   doctest MusicLibraryWeb.Markdown
 
+  describe "streaming" do
+    test "new document renders empty string" do
+      doc = Markdown.new_streaming_doc()
+      assert Markdown.streaming_to_html(doc) == ""
+    end
+
+    test "incremental chunks produce valid HTML" do
+      doc = Markdown.new_streaming_doc()
+      doc = MDEx.Document.put_markdown(doc, "**bold")
+      html = Markdown.streaming_to_html(doc)
+      assert html =~ "<strong>bold</strong>"
+
+      doc = MDEx.Document.put_markdown(doc, " text**")
+      html = Markdown.streaming_to_html(doc)
+      assert html =~ "<strong>bold text</strong>"
+    end
+
+    test "handles incomplete code fences" do
+      doc = Markdown.new_streaming_doc()
+      doc = MDEx.Document.put_markdown(doc, "```elixir\nIO.puts")
+      html = Markdown.streaming_to_html(doc)
+      assert html =~ "IO"
+      assert html =~ "puts"
+      assert html =~ "<code"
+    end
+
+    test "sanitizes script tags" do
+      doc = Markdown.new_streaming_doc()
+      doc = MDEx.Document.put_markdown(doc, "<script>alert(1)</script>")
+      html = Markdown.streaming_to_html(doc)
+      refute html =~ "<script>"
+    end
+  end
+
   describe "to_html/1" do
     test "strips script tags" do
       result = Markdown.to_html("<script>alert('xss')</script>")