test: add test for cache's ttl behavior

internal/datastore/proxy/schemacaching/standardcache.go

@@ -168,10 +168,6 @@ func listAndCache[T schemaDefinition](
 			entry := &cacheEntry{def.Definition, def.LastWrittenRevision, estimatedDefinitionSize, err}
 			r.p.c.Set(cache.StringKey(cacheRevisionKey), entry, entry.Size())
 		}
-
-		// We have to call wait here or else Ristretto may not have the key(s)
-		// available to a subsequent caller.
-		r.p.c.Wait()
 	}
 
 	return foundDefs, nil
@@ -203,9 +199,6 @@ func readAndCache[T schemaDefinition](
 			entry := &cacheEntry{loaded, updatedRev, estimatedDefinitionSize, err}
 			r.p.c.Set(cache.StringKey(cacheRevisionKey), entry, entry.Size())
 
-			// We have to call wait here or else Ristretto may not have the key
-			// available to a subsequent caller.
-			r.p.c.Wait()
 			return entry, nil
 		})
 		if err != nil {

pkg/cache/cache.go

@@ -75,13 +75,6 @@ type Cache[K KeyString, V any] interface {
 	// implementation, so writes are best-effort.
 	Set(key K, entry V, cost int64) bool
 
-	// Wait blocks until buffered Set calls have been processed by the
-	// underlying implementation. Required for read-your-own-writes
-	// semantics with implementations that buffer writes (e.g. Ristretto);
-	// a no-op on the current Otter-backed implementation, which applies
-	// writes synchronously.
-	Wait()
-
 	// Close stops the cache's background workers (if any) and tears down
 	// associated metrics registration, if one was set up.
 	Close()
@@ -118,7 +111,6 @@ var _ Cache[StringKey, any] = (*noopCache[StringKey, any])(nil)
 func (no *noopCache[K, V]) Get(_ K) (V, bool)          { return *new(V), false }
 func (no *noopCache[K, V]) GetTTL() time.Duration      { return time.Duration(0) }
 func (no *noopCache[K, V]) Set(_ K, _ V, _ int64) bool { return false }
-func (no *noopCache[K, V]) Wait()                      {}
 func (no *noopCache[K, V]) Close()                     {}
 func (no *noopCache[K, V]) GetMetrics() Metrics        { return &noopMetrics{} }
 func (no *noopCache[K, V]) MarshalZerologObject(e *zerolog.Event) {

pkg/cache/cache_otter.go

@@ -189,7 +189,6 @@ func (wtc *otterCache[K, V]) Set(key K, value V, cost int64) bool {
 	return true
 }
 
-func (wtc *otterCache[K, V]) Wait() {}
 func (wtc *otterCache[K, V]) Close() {
 	// Stops the pending goroutine that Otter spins off
 	wtc.cache.StopAllGoroutines()

pkg/cache/cache_test.go

@@ -3,9 +3,11 @@ package cache
 import (
 	"math"
 	"testing"
+	"testing/synctest"
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
@@ -32,7 +34,6 @@ func TestCostAddedIncludesKey(t *testing.T) {
 	const key = "some-key"
 	const payloadCost = 10
 	require.True(t, cache.Set(StringKey(key), "value", payloadCost))
-	cache.Wait()
 
 	// costAdded must reflect the full entry weight (payload + key bytes), not
 	// just the caller-supplied payload cost.
@@ -68,9 +69,6 @@ func TestCacheWithMetrics(t *testing.T) {
 			require.True(t, ok)
 		}
 
-		// Wait for all sets to be processed
-		cache.Wait()
-
 		// Verify all entries
 		for _, entry := range entries {
 			retrieved, found := cache.Get(entry.key)
@@ -86,15 +84,13 @@ func TestCacheWithMetrics(t *testing.T) {
 
 		ok := cache.Set(StringKey("metric-key-1"), "value1", 10)
 		require.True(t, ok)
-		cache.Wait()
 		val, found := cache.Get("metric-key-1")
 		require.True(t, found)
 		require.Equal(t, "value1", val)
 
 		// same key set, diff value
 		ok = cache.Set(StringKey("metric-key-1"), "value2", 10)
 		require.True(t, ok)
-		cache.Wait()
 		val, found = cache.Get("metric-key-1")
 		require.True(t, found)
 		require.Equal(t, "value2", val)
@@ -120,16 +116,16 @@ func TestCacheWithMetrics(t *testing.T) {
 	t.Run("GetMetrics", func(t *testing.T) {
 		cache, err := NewOtterCacheWithMetrics[StringKey, string](prometheus.NewRegistry(), "test-otter", config)
 		require.NoError(t, err)
-		defer cache.Close()
+		t.Cleanup(func() {
+			cache.Close()
+		})
 
 		// Set some values
 		ok := cache.Set(StringKey("metric-key-1"), "value1", 10)
 		require.True(t, ok)
 		ok = cache.Set(StringKey("metric-key-2"), "value2", 20)
 		require.True(t, ok)
 
-		cache.Wait()
-
 		// Perform some gets (hits and misses)
 		_, ok = cache.Get(StringKey("metric-key-1")) // hit
 		require.True(t, ok)
@@ -151,4 +147,38 @@ func TestCacheWithMetrics(t *testing.T) {
 		costAdded := metrics.CostAdded()
 		require.GreaterOrEqual(t, costAdded, uint64(10), "expected cost to be tracked")
 	})
+
+	t.Run("TTL Behavior", func(t *testing.T) {
+		synctest.Test(t, func(t *testing.T) {
+			cache, err := NewOtterCacheWithMetrics[StringKey, string](prometheus.NewRegistry(), "test-otter", &Config{
+				MaxCost: 1000,
+				// set a lower TTL
+				DefaultTTL: 1 * time.Minute,
+			})
+			//nolint:testifylint  // we're in a goroutine
+			if !assert.NoError(t, err) {
+				return
+			}
+
+			// Set and get a key
+			ok := cache.Set(StringKey("a key"), "a value", 10)
+			assert.True(t, ok)
+
+			// retrieve the key
+			retrieved, found := cache.Get(StringKey("a key"))
+			assert.True(t, found, "expected key %s to be found", "a key")
+			assert.Equal(t, "a value", retrieved, "expected value for key %s to match", "a key")
+
+			// wait for a bit
+			time.Sleep(3 * time.Minute)
+
+			// Retrieve the original key again; we're expecting not to find it.
+			_, found = cache.Get(StringKey("a key"))
+			assert.False(t, found, "expected key %s to be found", "a key")
+
+			cache.Close()
+
+			synctest.Wait()
+		})
+	})
 }

pkg/datalayer/datalayer_test.go

@@ -916,8 +916,6 @@ func (c *testSchemaCache) cost(key SchemaCacheKey) int64 {
 	return c.lastCosts[key]
 }
 
-func (c *testSchemaCache) Wait() {}
-
 // countingDatastore wraps a datastore.Datastore and counts ReadStoredSchema calls.
 type countingDatastore struct {
 	datastore.Datastore

pkg/datalayer/hashcache.go

@@ -36,7 +36,6 @@ func (k SchemaCacheKey) KeyString() string { return string(k) }
 type SchemaCache interface {
 	Get(key SchemaCacheKey) (*datastore.ReadOnlyStoredSchema, bool)
 	Set(key SchemaCacheKey, entry *datastore.ReadOnlyStoredSchema, cost int64) bool
-	Wait()
 }
 
 // latestSchemaEntry holds the most recent schema entry for fast-path lookups.

pkg/datalayer/hashcache_test.go

@@ -39,8 +39,6 @@ func TestSchemaHashCache_BasicGetSet(t *testing.T) {
 	err = shc.Set(SchemaHash("hash1"), schema)
 	require.NoError(t, err)
 
-	shc.cache.Wait()
-
 	retrieved, err = shc.get(SchemaHash("hash1"))
 	require.NoError(t, err)
 	require.NotNil(t, retrieved)
@@ -280,8 +278,6 @@ func TestSchemaHashCache_SlowPathCacheHit(t *testing.T) {
 	err = shc.Set(SchemaHash("hash2"), schema2)
 	require.NoError(t, err)
 
-	shc.cache.Wait()
-
 	// Get hash1 — latest is hash2, so fast path misses,
 	// but backing cache should have it (slow path hit, line 95)
 	retrieved, err := shc.get(SchemaHash("hash1"))