diff --git a/src/logging/diagnostic-session-context.test.ts b/src/logging/diagnostic-session-context.test.ts
index b0f50932a6f6..5c03fea1f816 100644
--- a/src/logging/diagnostic-session-context.test.ts
+++ b/src/logging/diagnostic-session-context.test.ts
@@ -4,6 +4,7 @@ import os from "node:os";
 import path from "node:path";
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
 import { saveCronStore } from "../cron/store.js";
+import { captureEnv } from "../test-utils/env.js";
 import {
   formatCronSessionDiagnosticFields,
   formatStoppedCronSessionDiagnosticFields,
@@ -13,7 +14,7 @@ import {
 } from "./diagnostic-session-context.js";
 
 let tempDir: string | undefined;
-let previousStateDir: string | undefined;
+let envSnapshot: ReturnType<typeof captureEnv> | undefined;
 
 function writeJsonl(filePath: string, rows: unknown[]) {
   fs.mkdirSync(path.dirname(filePath), { recursive: true });
@@ -22,17 +23,14 @@ function writeJsonl(filePath: string, rows: unknown[]) {
 
 describe("diagnostic session context", () => {
   beforeEach(() => {
-    previousStateDir = process.env.OPENCLAW_STATE_DIR;
+    envSnapshot = captureEnv(["OPENCLAW_STATE_DIR"]);
     tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "openclaw-diagnostic-session-"));
     process.env.OPENCLAW_STATE_DIR = tempDir;
   });
 
   afterEach(() => {
-    if (previousStateDir === undefined) {
-      delete process.env.OPENCLAW_STATE_DIR;
-    } else {
-      process.env.OPENCLAW_STATE_DIR = previousStateDir;
-    }
+    envSnapshot?.restore();
+    envSnapshot = undefined;
     if (tempDir) {
       fs.rmSync(tempDir, { recursive: true, force: true });
     }