verbose live UI + tool-level SSE events + Groq default + regression tests

tests/test_langfuse_client.py

@@ -0,0 +1,41 @@
+"""Regression: langfuse_client surface + span context manager behaviour.
+
+Bugs captured:
+1. AttributeError: module 'api.langfuse_client' has no attribute 'span'
+   — the module was at the old observability.py shape with `langfuse_span`.
+2. RuntimeError: generator didn't stop after throw()
+   — the @contextmanager wrapped the user's `with` body in `try/except`
+   and yielded a second value on exception, which @contextmanager rejects.
+"""
+
+import pytest
+
+from api import langfuse_client as lf
+
+
+def test_public_surface():
+    assert callable(lf.span)
+    assert callable(lf.flush)
+    assert callable(lf.get_client)
+
+
+def test_span_returns_nullspan_without_keys(monkeypatch):
+    # Ensure no keys → no client → null span.
+    from api.config import get_settings
+    get_settings.cache_clear()
+    monkeypatch.setenv("LANGFUSE_PUBLIC_KEY", "")
+    monkeypatch.setenv("LANGFUSE_SECRET_KEY", "")
+    # Reset cached client too
+    lf._client = None
+    with lf.span("t") as s:
+        assert isinstance(s, lf._NullSpan)
+        s.update(output={"x": 1})  # no-op should not raise
+    get_settings.cache_clear()
+
+
+def test_span_body_exception_propagates():
+    """The body's exception MUST propagate — wrapping it inside @contextmanager
+    causes 'generator didn't stop after throw()' if the except clause yields."""
+    with pytest.raises(ValueError, match="kaboom"):
+        with lf.span("t"):
+            raise ValueError("kaboom")