feat: 添加对 LiteLLM 嵌入后端的支持，增强并发 API 调用能力

codex-lens/tests/test_embedding_backend_availability.py

@@ -0,0 +1,67 @@
+"""Tests for embedding backend availability checks.
+
+These tests validate the logic used to decide whether embeddings generation
+should run for a given backend (fastembed vs. litellm).
+"""
+
+import pytest
+
+
+def test_is_embedding_backend_available_invalid_backend(monkeypatch):
+    import codexlens.semantic as semantic
+
+    ok, err = semantic.is_embedding_backend_available("nope")
+    assert ok is False
+    assert "Invalid embedding backend" in (err or "")
+
+
+def test_is_embedding_backend_available_fastembed_true(monkeypatch):
+    import codexlens.semantic as semantic
+
+    monkeypatch.setattr(semantic, "SEMANTIC_AVAILABLE", True)
+    ok, err = semantic.is_embedding_backend_available("fastembed")
+    assert ok is True
+    assert err is None
+
+
+def test_is_embedding_backend_available_fastembed_false(monkeypatch):
+    import codexlens.semantic as semantic
+
+    monkeypatch.setattr(semantic, "SEMANTIC_AVAILABLE", False)
+    monkeypatch.setattr(semantic, "_import_error", "fastembed missing")
+    ok, err = semantic.is_embedding_backend_available("fastembed")
+    assert ok is False
+    assert err == "fastembed missing"
+
+
+def test_is_embedding_backend_available_litellm_true(monkeypatch):
+    import codexlens.semantic as semantic
+
+    monkeypatch.setattr(semantic, "LITELLM_AVAILABLE", True)
+    ok, err = semantic.is_embedding_backend_available("litellm")
+    assert ok is True
+    assert err is None
+
+
+def test_is_embedding_backend_available_litellm_false(monkeypatch):
+    import codexlens.semantic as semantic
+
+    monkeypatch.setattr(semantic, "LITELLM_AVAILABLE", False)
+    ok, err = semantic.is_embedding_backend_available("litellm")
+    assert ok is False
+    assert "ccw-litellm not available" in (err or "")
+
+
+def test_generate_embeddings_uses_backend_availability_gate(monkeypatch, tmp_path):
+    from codexlens.cli import embedding_manager
+
+    monkeypatch.setattr(
+        embedding_manager,
+        "is_embedding_backend_available",
+        lambda _backend: (False, "blocked"),
+    )
+
+    result = embedding_manager.generate_embeddings(tmp_path / "_index.db", embedding_backend="litellm")
+    assert result["success"] is False
+    assert result["error"] == "blocked"
+