refactor: improve Ollama embedder, normalize model names, add error handling, update tests (#4403)

tests/embeddings/test_ollama_embeddings.py

@@ -19,13 +19,13 @@ def test_embed_text(mock_ollama_client):
     config = BaseEmbedderConfig(model="nomic-embed-text", embedding_dims=512)
     embedder = OllamaEmbedding(config)
 
-    mock_response = {"embedding": [0.1, 0.2, 0.3, 0.4, 0.5]}
-    mock_ollama_client.embeddings.return_value = mock_response
+    mock_response = {"embeddings": [[0.1, 0.2, 0.3, 0.4, 0.5]]}
+    mock_ollama_client.embed.return_value = mock_response
 
     text = "Sample text to embed."
     embedding = embedder.embed(text)
 
-    mock_ollama_client.embeddings.assert_called_once_with(model="nomic-embed-text", prompt=text)
+    mock_ollama_client.embed.assert_called_once_with(model="nomic-embed-text", input=text)
 
     assert embedding == [0.1, 0.2, 0.3, 0.4, 0.5]
 
@@ -41,3 +41,22 @@ def test_ensure_model_exists(mock_ollama_client):
     embedder._ensure_model_exists()
 
     mock_ollama_client.pull.assert_called_once_with("nomic-embed-text")
+
+
+def test_ensure_model_exists_normalizes_latest_tag(mock_ollama_client):
+    """Model 'nomic-embed-text' should match 'nomic-embed-text:latest' from ollama list."""
+    mock_ollama_client.list.return_value = {"models": [{"name": "nomic-embed-text:latest"}]}
+    config = BaseEmbedderConfig(model="nomic-embed-text", embedding_dims=512)
+    OllamaEmbedding(config)
+
+    mock_ollama_client.pull.assert_not_called()
+
+
+def test_embed_empty_response_raises(mock_ollama_client):
+    config = BaseEmbedderConfig(model="nomic-embed-text", embedding_dims=512)
+    embedder = OllamaEmbedding(config)
+
+    mock_ollama_client.embed.return_value = {"embeddings": []}
+
+    with pytest.raises(ValueError, match="returned no embeddings"):
+        embedder.embed("some text")