fix(go-models): harden Hunyuan embedding validation (#15249)

## Summary
- Validate Hunyuan embedding model name and API key before building
requests.
- Reuse region-aware base URL validation for embedding requests.
- Replace the stale unsupported Embed test with happy-path and
validation coverage.

## What changed
- Added early Hunyuan Embed validation for missing model names and API
keys.
- Routed Embed through the same base URL region guard used by the other
Hunyuan methods.
- Updated Hunyuan tests to configure the embedding suffix and cover
Embed success plus invalid inputs.

## Why
Hunyuan Embed is implemented, but the existing test still expected it to
be unsupported and could panic before returning a normal validation
error. This keeps the implemented embedding path aligned with the
current driver behavior and prevents nil input panics.

Closes #15087
Refs #14736

internal/entity/models/hunyuan.go

@@ -440,13 +440,23 @@ func (a *HunyuanModel) Embed(modelName *string, texts []string, apiConfig *APICo
 	if len(texts) == 0 {
 		return []EmbeddingData{}, nil
 	}
+	if modelName == nil || *modelName == "" {
+		return nil, fmt.Errorf("model name is required")
+	}
+	if apiConfig == nil || apiConfig.ApiKey == nil || *apiConfig.ApiKey == "" {
+		return nil, fmt.Errorf("api key is required")
+	}
 
 	var region = "default"
-	if apiConfig != nil && apiConfig.Region != nil && *apiConfig.Region != "" {
+	if apiConfig.Region != nil && *apiConfig.Region != "" {
 		region = *apiConfig.Region
 	}
 
-	url := fmt.Sprintf("%s/%s", a.BaseURL[region], a.URLSuffix.Embedding)
+	baseURL, err := a.baseURLForRegion(region)
+	if err != nil {
+		return nil, err
+	}
+	url := fmt.Sprintf("%s/%s", baseURL, a.URLSuffix.Embedding)
 
 	reqBody := map[string]interface{}{
 		"model": *modelName,
@@ -458,7 +468,10 @@ func (a *HunyuanModel) Embed(modelName *string, texts []string, apiConfig *APICo
 		return nil, fmt.Errorf("failed to marshal request: %w", err)
 	}
 
-	req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonData))
+	ctx, cancel := context.WithTimeout(context.Background(), nonStreamCallTimeout)
+	defer cancel()
+
+	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewBuffer(jsonData))
 	if err != nil {
 		return nil, fmt.Errorf("failed to create request: %w", err)
 	}
@@ -496,7 +509,7 @@ func (a *HunyuanModel) Embed(modelName *string, texts []string, apiConfig *APICo
 		return nil, fmt.Errorf("hunyuan embedding response contains no data: %s", string(body))
 	}
 
-	var embeddings []EmbeddingData
+	embeddings := make([]EmbeddingData, 0, len(parsedResponse.Data))
 	for _, dataElem := range parsedResponse.Data {
 		embeddings = append(embeddings, EmbeddingData{
 			Embedding: dataElem.Embedding,

internal/entity/models/hunyuan_test.go

@@ -75,7 +75,7 @@ func newHunyuanSSEServer(t *testing.T, expectedPath, ssePayload string) *httptes
 func newHunyuanForTest(baseURL string) *HunyuanModel {
 	return NewHunyuanModel(
 		map[string]string{"default": baseURL},
-		URLSuffix{Chat: "chat/completions", Models: "models"},
+		URLSuffix{Chat: "chat/completions", Embedding: "embeddings", Models: "models"},
 	)
 }
 
@@ -428,11 +428,60 @@ func TestHunyuanBaseURLForRegionUnknown(t *testing.T) {
 	}
 }
 
-func TestHunyuanEmbedReturnsNoSuchMethod(t *testing.T) {
-	model := "x"
-	_, err := newHunyuanForTest("http://unused").Embed(&model, []string{"a"}, &APIConfig{}, nil)
-	if err == nil || !strings.Contains(err.Error(), "no such method") {
-		t.Errorf("Embed: want 'no such method', got %v", err)
+func TestHunyuanEmbedHappyPath(t *testing.T) {
+	srv := newHunyuanServer(t, http.MethodPost, "/embeddings", func(t *testing.T, body map[string]interface{}, w http.ResponseWriter) {
+		if body["model"] != "hunyuan-embedding" {
+			t.Errorf("model=%v", body["model"])
+		}
+		inputs, ok := body["input"].([]interface{})
+		if !ok || len(inputs) != 2 {
+			t.Errorf("input=%#v", body["input"])
+			http.Error(w, "bad input", http.StatusBadRequest)
+			return
+		}
+		_ = json.NewEncoder(w).Encode(map[string]interface{}{
+			"data": []map[string]interface{}{
+				{"embedding": []float64{0.1, 0.2}, "index": 0},
+				{"embedding": []float64{0.3, 0.4}, "index": 1},
+			},
+		})
+	})
+	defer srv.Close()
+
+	apiKey := "test-key"
+	model := "hunyuan-embedding"
+	embeddings, err := newHunyuanForTest(srv.URL).Embed(&model, []string{"a", "b"}, &APIConfig{ApiKey: &apiKey}, nil)
+	if err != nil {
+		t.Fatalf("Embed: %v", err)
+	}
+	if len(embeddings) != 2 || embeddings[1].Index != 1 || embeddings[1].Embedding[0] != 0.3 {
+		t.Errorf("embeddings=%+v", embeddings)
+	}
+}
+
+func TestHunyuanEmbedValidatesInputs(t *testing.T) {
+	apiKey := "test-key"
+	model := "hunyuan-embedding"
+
+	if embeddings, err := newHunyuanForTest("http://unused").Embed(nil, nil, nil, nil); err != nil || len(embeddings) != 0 {
+		t.Errorf("empty input: embeddings=%+v err=%v", embeddings, err)
+	}
+	if _, err := newHunyuanForTest("http://unused").Embed(nil, []string{"x"}, &APIConfig{ApiKey: &apiKey}, nil); err == nil || !strings.Contains(err.Error(), "model name is required") {
+		t.Errorf("nil model: %v", err)
+	}
+	emptyModel := ""
+	if _, err := newHunyuanForTest("http://unused").Embed(&emptyModel, []string{"x"}, &APIConfig{ApiKey: &apiKey}, nil); err == nil || !strings.Contains(err.Error(), "model name is required") {
+		t.Errorf("empty model: %v", err)
+	}
+	if _, err := newHunyuanForTest("http://unused").Embed(&model, []string{"x"}, nil, nil); err == nil || !strings.Contains(err.Error(), "api key is required") {
+		t.Errorf("nil api config: %v", err)
+	}
+	if _, err := newHunyuanForTest("http://unused").Embed(&model, []string{"x"}, &APIConfig{}, nil); err == nil || !strings.Contains(err.Error(), "api key is required") {
+		t.Errorf("missing api key: %v", err)
+	}
+	emptyKey := ""
+	if _, err := newHunyuanForTest("http://unused").Embed(&model, []string{"x"}, &APIConfig{ApiKey: &emptyKey}, nil); err == nil || !strings.Contains(err.Error(), "api key is required") {
+		t.Errorf("empty api key: %v", err)
 	}
 }