feat: add gemini image test preview

backend/internal/service/account_test_service_gemini_test.go

@@ -0,0 +1,59 @@
+//go:build unit
+
+package service
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCreateGeminiTestPayload_ImageModel(t *testing.T) {
+	t.Parallel()
+
+	payload := createGeminiTestPayload("gemini-2.5-flash-image", "draw a tiny robot")
+
+	var parsed struct {
+		Contents []struct {
+			Parts []struct {
+				Text string `json:"text"`
+			} `json:"parts"`
+		} `json:"contents"`
+		GenerationConfig struct {
+			ResponseModalities []string `json:"responseModalities"`
+			ImageConfig        struct {
+				AspectRatio string `json:"aspectRatio"`
+			} `json:"imageConfig"`
+		} `json:"generationConfig"`
+	}
+
+	require.NoError(t, json.Unmarshal(payload, &parsed))
+	require.Len(t, parsed.Contents, 1)
+	require.Len(t, parsed.Contents[0].Parts, 1)
+	require.Equal(t, "draw a tiny robot", parsed.Contents[0].Parts[0].Text)
+	require.Equal(t, []string{"TEXT", "IMAGE"}, parsed.GenerationConfig.ResponseModalities)
+	require.Equal(t, "1:1", parsed.GenerationConfig.ImageConfig.AspectRatio)
+}
+
+func TestProcessGeminiStream_EmitsImageEvent(t *testing.T) {
+	t.Parallel()
+	gin.SetMode(gin.TestMode)
+
+	ctx, recorder := newSoraTestContext()
+	svc := &AccountTestService{}
+
+	stream := strings.NewReader("data: {\"candidates\":[{\"content\":{\"parts\":[{\"text\":\"ok\"},{\"inlineData\":{\"mimeType\":\"image/png\",\"data\":\"QUJD\"}}]}}]}\n\ndata: [DONE]\n\n")
+
+	err := svc.processGeminiStream(ctx, stream)
+	require.NoError(t, err)
+
+	body := recorder.Body.String()
+	require.Contains(t, body, "\"type\":\"content\"")
+	require.Contains(t, body, "\"text\":\"ok\"")
+	require.Contains(t, body, "\"type\":\"image\"")
+	require.Contains(t, body, "\"image_url\":\"data:image/png;base64,QUJD\"")
+	require.Contains(t, body, "\"mime_type\":\"image/png\"")
+}