fix: avoid temp unsched when refresh token is missing

backend/internal/service/openai_oauth_service_refresh_test.go

@@ -0,0 +1,54 @@
+package service
+
+import (
+	"context"
+	"errors"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/openai"
+	"github.com/stretchr/testify/require"
+)
+
+type openaiOAuthClientRefreshStub struct {
+	refreshCalls int32
+}
+
+func (s *openaiOAuthClientRefreshStub) ExchangeCode(ctx context.Context, code, codeVerifier, redirectURI, proxyURL, clientID string) (*openai.TokenResponse, error) {
+	return nil, errors.New("not implemented")
+}
+
+func (s *openaiOAuthClientRefreshStub) RefreshToken(ctx context.Context, refreshToken, proxyURL string) (*openai.TokenResponse, error) {
+	atomic.AddInt32(&s.refreshCalls, 1)
+	return nil, errors.New("not implemented")
+}
+
+func (s *openaiOAuthClientRefreshStub) RefreshTokenWithClientID(ctx context.Context, refreshToken, proxyURL string, clientID string) (*openai.TokenResponse, error) {
+	atomic.AddInt32(&s.refreshCalls, 1)
+	return nil, errors.New("not implemented")
+}
+
+func TestOpenAIOAuthService_RefreshAccountToken_NoRefreshTokenUsesExistingAccessToken(t *testing.T) {
+	client := &openaiOAuthClientRefreshStub{}
+	svc := NewOpenAIOAuthService(nil, client)
+
+	expiresAt := time.Now().Add(30 * time.Minute).UTC().Format(time.RFC3339)
+	account := &Account{
+		ID:       77,
+		Platform: PlatformOpenAI,
+		Type:     AccountTypeOAuth,
+		Credentials: map[string]any{
+			"access_token": "existing-access-token",
+			"expires_at":   expiresAt,
+			"client_id":    "client-id-1",
+		},
+	}
+
+	info, err := svc.RefreshAccountToken(context.Background(), account)
+	require.NoError(t, err)
+	require.NotNil(t, info)
+	require.Equal(t, "existing-access-token", info.AccessToken)
+	require.Equal(t, "client-id-1", info.ClientID)
+	require.Zero(t, atomic.LoadInt32(&client.refreshCalls), "existing access token should be reused without calling refresh")
+}