Fix 6816 sign test delay

[yykaue]

Fixes #6816

What this PR does

Explicitly initialize the sign verification delay in SignServiceVersionOneTest and SignServiceVersionTwoTest.

Previously, both test classes constructed ComposableSignService directly with new. As a result, Spring did not process its @Value field, leaving delay at the JVM default value of 0.

This could make success-expecting tests fail intermittently when timestamp creation and verification crossed a minute boundary.

This PR:

• Uses an explicit DELAY = 5 test constant.
• Injects the delay into manually constructed ComposableSignService instances with ReflectionTestUtils.
• Removes the ineffective @Value fields from the test classes.
• Adds regression tests verifying that valid signatures from one minute earlier succeed.
• Updates overdue tests to use the same configured delay.

Tests

./mvnw -pl shenyu-plugin/shenyu-plugin-security/shenyu-plugin-sign test
Tests run: 41, Failures: 0, Errors: 0, Skipped: 0

[Aias00]

Review: Fix #6816 sign test delay

Verdict: ✅ Approve

What it fixes

SignServiceVersionOneTest and SignServiceVersionTwoTest built ComposableSignService with new, so Spring never processed the service's @Value("${shenyu.sign.delay:5}") — delay stayed at the JVM default 0. The tests' own @Value private int delay field was dead code (never propagated to the service), so the success-path verification window was effectively zero tolerance. When sign-timestamp creation and signatureVerify crossed a minute boundary, a valid signature was rejected as overdue → intermittent failures.

Why the fix is correct

• ComposableSignService.delay is confirmed to exist (field private int delay, line 81, @Value("${shenyu.sign.delay:5}")); ReflectionTestUtils.setField(signService, "delay", DELAY) correctly injects 5 minutes, matching the intended production default.
• Verification uses Math.abs(between) <= delay (ms vs delay*60_000), so a 5-minute window now actually applies in tests.
• Removes the two ineffective @Value fields from the test classes (they were never wired in) — clean.

Test validity (verified)

normalTestWithinConfiguredDelay signs with timestamp = now - 60_000ms (1 min earlier) and expects success(). Under delay=0 this would be overdue and fail; under delay=5 it passes — so the test genuinely guards the intended behavior rather than just passing by accident. overdueTest now uses DELAY + 1 minutes and the matching error-message format. PR reports Tests run: 41, Failures: 0.

Conclusion

Correct, well-targeted test-stability fix with a meaningful regression test. Approved.

(Reviewed as part of a descending re-pass of open PRs; this PR is new since the last review cycle.)