diff --git a/haiku_rag_slim/haiku/rag/client.py b/haiku_rag_slim/haiku/rag/client.py
index 056446fe..b2507493 100644
--- a/haiku_rag_slim/haiku/rag/client.py
+++ b/haiku_rag_slim/haiku/rag/client.py
@@ -1681,7 +1681,9 @@ class HaikuRAG:
         yield DownloadProgress(model=tokenizer_name, status="done")
 
         # Sentence-transformers embedder
-        if self._config.embeddings.model.provider == "sentence-transformers":
+        if (
+            self._config.embeddings.model.provider == "sentence-transformers"
+        ):  # pragma: no cover
             try:
                 from sentence_transformers import (  # type: ignore[import-not-found]
                     SentenceTransformer,
@@ -1695,7 +1697,7 @@ class HaikuRAG:
                 pass
 
         # HuggingFace reranker models
-        if self._config.reranking.model:
+        if self._config.reranking.model:  # pragma: no cover
             provider = self._config.reranking.model.provider
             model_name = self._config.reranking.model.name
 
diff --git a/haiku_rag_slim/haiku/rag/reranking/jina_local.py b/haiku_rag_slim/haiku/rag/reranking/jina_local.py
index 2f8a228f..bbe97898 100644
--- a/haiku_rag_slim/haiku/rag/reranking/jina_local.py
+++ b/haiku_rag_slim/haiku/rag/reranking/jina_local.py
@@ -12,7 +12,7 @@ from haiku.rag.reranking.base import RerankerBase
 from haiku.rag.store.models.chunk import Chunk
 
 
-class JinaLocalReranker(RerankerBase):
+class JinaLocalReranker(RerankerBase):  # pragma: no cover
     """Jina reranker using local model inference via transformers.
 
     Note: The Jina Reranker v3 model is licensed under CC BY-NC 4.0,
diff --git a/tests/test_reranker.py b/tests/test_reranker.py
index 74f19b6f..8d1d3f9f 100644
--- a/tests/test_reranker.py
+++ b/tests/test_reranker.py
@@ -235,6 +235,26 @@ class TestGetReranker:
             pytest.skip("Jina local dependencies not installed")
 
 
+def test_jina_reranker_missing_api_key(monkeypatch):
+    monkeypatch.delenv("JINA_API_KEY", raising=False)
+
+    from haiku.rag.reranking.jina import JinaReranker
+
+    with pytest.raises(ValueError, match="JINA_API_KEY environment variable required"):
+        JinaReranker("jina-reranker-v3")
+
+
+@pytest.mark.asyncio
+async def test_jina_reranker_empty_chunks(monkeypatch):
+    monkeypatch.setenv("JINA_API_KEY", "test-api-key")
+
+    from haiku.rag.reranking.jina import JinaReranker
+
+    reranker = JinaReranker("jina-reranker-v3")
+    result = await reranker.rerank("query", [], top_n=2)
+    assert result == []
+
+
 @pytest.mark.asyncio
 @pytest.mark.vcr()
 async def test_jina_reranker(monkeypatch):