fix(test): Use synctest to deflake timer-based tests.

[Fletch153]

Summary

Use synctest in TestPlugin_GetLatencies and TestScheduledExecutionStrategy_LocalDON.

Root Cause

The race detector adds 5-10x overhead to memory operations. Tests with absolute timing assertions and only 100ms margins fail intermittently under -race or CI CPU pressure.

Test plan

• TestScheduledExecutionStrategy_LocalDON passes with -count=50 -race locally
• CI passes

Fixes: CORE-2382

[github-actions]

✅ No conflicts with other open PRs targeting develop

[trunk-io]

     

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[Fletch153]

/rerun

[Fletch153]

Closing — widening timing margins is a band-aid. The test still uses absolute timing assertions that are inherently flaky under load. A proper fix would either remove the upper-bound assertions or test relative ordering instead of absolute windows.

[github-actions]

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[Copilot]

Pull request overview

Risk Rating: LOW — primarily test-only changes; one small production change (mutable cache defaults) that can affect behavior if unintentionally modified.

This PR deflakes timer-based tests by switching them to Go’s testing/synctest so timing assertions are deterministic under -race and CI load.

Changes:

• Use testing/synctest in TestPlugin_GetLatencies to avoid real-time sleeps and tighten duration assertions.
• Use testing/synctest in TestScheduledExecutionStrategy_LocalDON to stabilize timer-based scheduling assertions.
• Make promwrapper cache cleanup defaults overridable from tests (by changing cache defaults from const to var and overriding defaultCleanupInterval in the test).

Scrupulous human review areas:

• core/services/ocr2/plugins/promwrapper/plugin.go: introduction of mutable package-level defaults (defaultExpiration, defaultCleanupInterval) and how/where they can be mutated.
• core/services/ocr2/plugins/promwrapper/plugin_test.go: global override of defaultCleanupInterval and ensuring it’s restored and properly scoped to the synctest run.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
core/services/ocr2/plugins/promwrapper/plugin.go	Makes cache default timings mutable to allow tests to disable go-cache GC under synctest.
core/services/ocr2/plugins/promwrapper/plugin_test.go	Wraps latency test in synctest and disables cache GC to avoid synctest incompatibility.
core/capabilities/transmission/local_target_capability_test.go	Uses synctest for deterministic schedule/timer assertions.

Comments suppressed due to low confidence (1)

core/services/ocr2/plugins/promwrapper/plugin.go:26

• Only defaultCleanupInterval needs to be overridable for synctest; turning defaultExpiration into a mutable package-level variable is unnecessary and increases the surface for accidental mutation. Consider keeping defaultExpiration as a const and defining defaultCleanupInterval as a separate var (or exposing it via a constructor/option for tests).

// var instead of const to make it overridable in tests
var (
	// defaultExpiration is the default expiration time for cache items.
	defaultExpiration = 30 * time.Minute

	// defaultCleanupInterval is the default interval for cache cleanup.
	defaultCleanupInterval = 5 * time.Minute
)

[cl-sonarqube-production]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarQube