feat: add tests and update mds

tests/tui_gateway/test_render.py

@@ -0,0 +1,67 @@
+"""Tests for tui_gateway.render — rendering bridge fallback behavior."""
+
+from unittest.mock import MagicMock, patch
+
+from tui_gateway.render import make_stream_renderer, render_diff, render_message
+
+
+def _stub_rich(mock_mod):
+    return patch.dict("sys.modules", {"agent.rich_output": mock_mod})
+
+
+def _no_rich():
+    return patch.dict("sys.modules", {"agent.rich_output": None})
+
+
+# ── render_message ───────────────────────────────────────────────────
+
+
+def test_render_message_none_without_module():
+    with _no_rich():
+        assert render_message("hello") is None
+
+
+def test_render_message_formatted():
+    mod = MagicMock()
+    mod.format_response.return_value = "<b>hi</b>"
+
+    with _stub_rich(mod):
+        assert render_message("hi", 100) == "<b>hi</b>"
+
+
+def test_render_message_type_error_fallback():
+    mod = MagicMock()
+    mod.format_response.side_effect = [TypeError, "fallback"]
+
+    with _stub_rich(mod):
+        assert render_message("hi") == "fallback"
+
+
+def test_render_message_exception_returns_none():
+    mod = MagicMock()
+    mod.format_response.side_effect = RuntimeError
+
+    with _stub_rich(mod):
+        assert render_message("hi") is None
+
+
+# ── render_diff / make_stream_renderer ───────────────────────────────
+
+
+def test_render_diff_none_without_module():
+    with _no_rich():
+        assert render_diff("+line") is None
+
+
+def test_stream_renderer_none_without_module():
+    with _no_rich():
+        assert make_stream_renderer() is None
+
+
+def test_stream_renderer_returns_instance():
+    renderer = MagicMock()
+    mod = MagicMock()
+    mod.StreamingRenderer.return_value = renderer
+
+    with _stub_rich(mod):
+        assert make_stream_renderer(120) is renderer