refactor(test): dedupe qianfan env restore

src/agents/models-config.providers.qianfan.e2e.test.ts

@@ -2,12 +2,13 @@ import { mkdtempSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { describe, expect, it } from "vitest";
+import { captureEnv } from "../test-utils/env.js";
 import { resolveImplicitProviders } from "./models-config.providers.js";
 
 describe("Qianfan provider", () => {
   it("should include qianfan when QIANFAN_API_KEY is configured", async () => {
     const agentDir = mkdtempSync(join(tmpdir(), "openclaw-test-"));
-    const previous = process.env.QIANFAN_API_KEY;
+    const envSnapshot = captureEnv(["QIANFAN_API_KEY"]);
     process.env.QIANFAN_API_KEY = "test-key";
 
     try {
@@ -15,11 +16,7 @@ describe("Qianfan provider", () => {
       expect(providers?.qianfan).toBeDefined();
       expect(providers?.qianfan?.apiKey).toBe("QIANFAN_API_KEY");
     } finally {
-      if (previous === undefined) {
-        delete process.env.QIANFAN_API_KEY;
-      } else {
-        process.env.QIANFAN_API_KEY = previous;
-      }
+      envSnapshot.restore();
     }
   });
 });