[test] Add tests for syncutil.TTLCache.GetOrCreate with maxSize <= 0

[github-actions]

Test Coverage Improvement: TTLCache.GetOrCreate

Function Analyzed

• Package: internal/syncutil
• Function: (*TTLCache[K, V]).GetOrCreate
• Previous Coverage: 97.7% (package), 96.2% (function)
• New Coverage: 100.0% (package), 100.0% (function)
• Complexity: Medium — TTL eviction, LRU eviction, concurrent locking, and now the passthrough (maxSize <= 0) code path

Why This Function?

Running go test -coverprofile=coverage.out ./internal/syncutil/... revealed that TTLCache.GetOrCreate had one uncovered branch:

func (c *TTLCache[K, V]) GetOrCreate(key K, create func() V) V {
    if c.maxSize <= 0 {
        return create()  // ← NOT COVERED
    }
    // ... cache lookup, TTL eviction, LRU eviction ...
}

When maxSize is zero or negative, GetOrCreate intentionally becomes a passthrough: it calls create() on every invocation and never stores anything. This is a deliberate design choice that lets callers disable caching without modifying call-sites. The branch existed but had zero test coverage.

Tests Added

• ✅ maxSize = 0 — boundary value; cache is fully disabled
• ✅ maxSize = -1 — negative value; cache is disabled
• ✅ maxSize = -100 — large negative; cache is disabled
• ✅ Verifies create() is called on every invocation (no caching)
• ✅ Verifies successive calls return fresh values (not a cached result)
• ✅ Verifies Len() always returns 0 (nothing is stored)

Coverage Report

Before:
github.com/github/gh-aw-mcpg/internal/syncutil/ttl_cache.go:56:  GetOrCreate  96.2%
total: (statements) 97.7%

After:
github.com/github/gh-aw-mcpg/internal/syncutil/ttl_cache.go:56:  GetOrCreate  100.0%
total: (statements) 100.0%

Improvement: +2.3pp (package), +3.8pp (function)

Test Execution

All tests pass:

=== RUN   TestTTLCache_GetOrCreate_MaxSizeZeroOrNegativeBypassesCache
=== RUN   TestTTLCache_GetOrCreate_MaxSizeZeroOrNegativeBypassesCache/zero_disables_cache
=== RUN   TestTTLCache_GetOrCreate_MaxSizeZeroOrNegativeBypassesCache/negative_one_disables_cache
=== RUN   TestTTLCache_GetOrCreate_MaxSizeZeroOrNegativeBypassesCache/large_negative_disables_cache
--- PASS: TestTTLCache_GetOrCreate_MaxSizeZeroOrNegativeBypassesCache (0.00s)
ok  github.com/github/gh-aw-mcpg/internal/syncutil  0.205s  coverage: 100.0% of statements

---

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[Copilot]

Pull request overview

This PR improves test coverage for internal/syncutil.TTLCache.GetOrCreate by adding a focused unit test for the maxSize <= 0 passthrough behavior, ensuring the previously uncovered early-return branch is exercised.

Changes:

• Added a table-driven test that verifies maxSize = 0 and negative values disable caching.
• Asserts create() is invoked on every call (even for the same key), returns fresh values, and Len() remains 0.

Show a summary per file

File	Description
internal/syncutil/ttl_cache_test.go	Adds coverage for the maxSize <= 0 GetOrCreate passthrough path (no storage, always calls create()).

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• Files reviewed: 1/1 changed files
• Comments generated: 0