Extract shared build_metric_registry factory (DRY)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

tests/test_metric_registry.py

@@ -0,0 +1,27 @@
+"""Tests for the shared metric registry factory."""
+
+from unittest.mock import MagicMock
+
+from ragas.llms.base import InstructorBaseRagasLLM
+from ragas.embeddings.base import BaseRagasEmbedding
+
+from rag_eval.metrics.factory import build_metric_registry
+
+
+def _mock_llm():
+    """Return a mock that passes RAGAS InstructorLLM type checks."""
+    return MagicMock(spec=InstructorBaseRagasLLM)
+
+
+def _mock_emb():
+    """Return a mock that passes RAGAS embedding type checks."""
+    return MagicMock(spec=BaseRagasEmbedding)
+
+
+def test_build_metric_registry_has_all_seven_metrics():
+    """The registry exposes every supported metric keyed by its canonical name."""
+    registry = build_metric_registry(llm=_mock_llm(), embeddings=_mock_emb())
+    assert set(registry) == {
+        "faithfulness", "answer_relevancy", "context_recall", "context_precision",
+        "noise_sensitivity", "factual_correctness", "semantic_similarity",
+    }