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Question 73 of 100
API Security Testing
Advanced
Q73: How Do You Test Token Expiration and Refresh Mechanisms?
🎫Core Concept
How Do You Test Token Expiration and Refresh Mechanisms?
Key Takeaways & Architecture Summary
- ✓Mock or configure short-lived tokens (e.g. 5 seconds) for test runs.
- ✓Verify that requests with expired tokens yield HTTP 401 Unauthorized.
- ✓Verify that refresh tokens successfully fetch new access tokens.
Direct Answer Summary
Testing token expiration involves generating a token with a very short time-to-live (TTL), waiting for it to expire, and asserting that the API rejects it with an HTTP 401 status. You then verify the refresh flow, ensuring the client can use the refresh token to retrieve a new active access token.
⚠️ Senior Engineering Warning (Red Flag)
Never assume refresh tokens are permanent. Test that refresh tokens are expired automatically when the user changes passwords or logs out, preventing replay attacks.
💡 STAR Architectural Explanation & Pro Tip
Testing these mechanisms prevents integration issues in production apps, ensuring that web clients can renew expired sessions silently without interrupting the user experience.
RestAssuredTest.java
Rest-Assured + Java// Rest-Assured automated refresh token flow validation
Response refreshResponse = RestAssured.given()
.formParam("grant_type", "refresh_token")
.formParam("refresh_token", "active_refresh_token_string")
.post("/oauth/token");
refreshResponse.then().statusCode(200).body("access_token", Matchers.notNullValue());