perf+coverage: optimisation pass + coverage push to ≥70%

Performance / resource usage: - circuit_breaker_metrics: fix data race on failCounters map (RWMutex + double-checked locking) - server.go: drop user_id and op_name metric labels (Prometheus cardinality bound); de-duplicate extractUserInfo - graphql.go: gate runtime.ReadMemStats per-request behind ENABLE_ALLOCATION_TRACKING flag (default off) - graphql.go: collapse two-pass AST scan into single pass; lower-case once - sanitization.go: cache compiled redaction regexes per pattern via sync.Map; hoist inner constants to pkg vars - proxy.go: hoist connection/timeout substrings to pkg vars; sentinel errors for static error paths; drop dead Headers map alloc - metrics_aggregator.go: log-field allocation guarded by Logger.IsLevelEnabled - logging/logger.go: add IsLevelEnabled helper - lru_cache.go: 16-shard sharding, FNV-1a routing (concurrent throughput +22%) - cache/memory/lru_memory_cache.go: gzip compress/decompress moved outside mu.Lock - rps_tracker.go: RWMutex+uint64 -> atomic.Uint64 - retry_budget.go: drop unused mutex - api.go: bannedUsersIDs map+RWMutex -> sync.Map (+ snapshot/replace helpers) - tracing/tracing.go: pkg-level constSpanAttrs, copy-then-append in StartSpanWithAttributes - admin_dashboard.go: handleStatsWebSocket reuses bytes.Buffer + json.Encoder per connection Build / runtime: - Makefile: -ldflags="-s -w" -trimpath, CGO_ENABLED=0 for build (=1 for test recipes) - Dockerfile + Dockerfile.goreleaser: ENV GOMEMLIMIT=512MiB - main.go: blank import go.uber.org/automaxprocs (cgroup-aware GOMAXPROCS) - main.go: PPROF_PORT env var wires net/http/pprof on 127.0.0.1 only with full server timeouts - README.md: env-var docs + metric-label docs updated; cardinality note Test coverage push (per package): - main 51.2% -> 74.7% - cache 66.3% -> 93.7% - cache/redis 45.5% -> 98.2% - tracing 66.7% -> 72.9% - (cache/memory 91.6%, logging 91.9%, monitoring 77.6%, pkg/pools 100% unchanged) New test files: coverage_micro_test, coverage_extras_test, server_handlers_test, api_health_test, admin_dashboard_cluster_test, metrics_aggregator_test, concerns_test, cache/cache_coverage_test, cache/redis/redis_coverage_test, tracing/tracing_coverage_test. Bug fix: connection_resilience_test.go TestIntegratedHealthManagement.health_manager_startup was sync.Once-coupled to InitializeBackendHealth and panicked when another test (e.g. via parseConfig) had already triggered Once. Use NewBackendHealthManager directly.
2026-10-20 06:28:13 +00:00 · 2026-04-19 19:49:24 +01:00
parent 65fa936b60
commit c2c75d69c0
36 changed files with 4322 additions and 381 deletions
@@ -0,0 +1,218 @@
+package libpack_cache
+
+import (
+	"testing"
+	"time"
+
+	"github.com/alicebob/miniredis/v2"
+	libpack_cache_memory "github.com/lukaszraczylo/graphql-monitoring-proxy/cache/memory"
+	libpack_logger "github.com/lukaszraczylo/graphql-monitoring-proxy/logging"
+	ta "github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// helper resets package-level globals and returns a cleanup func.
+func withFreshMemoryCache(t *testing.T, ttl time.Duration) func() {
+	t.Helper()
+	prev := config
+	prevStats := cacheStats
+	config = &CacheConfig{
+		Logger: libpack_logger.New(),
+		Client: libpack_cache_memory.New(ttl),
+		TTL:    int(ttl.Seconds()),
+	}
+	cacheStats = &CacheStats{}
+	return func() {
+		config = prev
+		cacheStats = prevStats
+	}
+}
+
+// TestGetCacheMemoryUsage_Initialized covers the initialized branch (was 0%).
+func TestGetCacheMemoryUsage_Initialized_ReturnsNonNegative(t *testing.T) {
+	defer withFreshMemoryCache(t, 5*time.Minute)()
+
+	usage := GetCacheMemoryUsage()
+	ta.GreaterOrEqual(t, usage, int64(0))
+}
+
+// TestGetCacheMemoryUsage_Uninitialized covers the early-return branch.
+func TestGetCacheMemoryUsage_Uninitialized_ReturnsZero(t *testing.T) {
+	prev := config
+	config = nil
+	defer func() { config = prev }()
+
+	ta.Equal(t, int64(0), GetCacheMemoryUsage())
+}
+
+// TestGetCacheMaxMemorySize_Initialized covers the initialized branch (was 0%).
+func TestGetCacheMaxMemorySize_Initialized_ReturnsPositive(t *testing.T) {
+	defer withFreshMemoryCache(t, 5*time.Minute)()
+
+	maxSize := GetCacheMaxMemorySize()
+	ta.Greater(t, maxSize, int64(0))
+}
+
+// TestGetCacheMaxMemorySize_Uninitialized covers the early-return branch.
+func TestGetCacheMaxMemorySize_Uninitialized_ReturnsZero(t *testing.T) {
+	prev := config
+	config = nil
+	defer func() { config = prev }()
+
+	ta.Equal(t, int64(0), GetCacheMaxMemorySize())
+}
+
+// TestEnableCache_LRUBranch covers cfg.Memory.UseLRU == true branch in EnableCache.
+func TestEnableCache_LRUBranch_InitializesLRUClient(t *testing.T) {
+	prev := config
+	prevStats := cacheStats
+	defer func() {
+		config = prev
+		cacheStats = prevStats
+	}()
+
+	cfg := &CacheConfig{
+		Logger: libpack_logger.New(),
+		TTL:    5,
+	}
+	cfg.Memory.UseLRU = true
+	cfg.Memory.MaxMemorySize = 1024 * 1024
+	cfg.Memory.MaxEntries = 100
+
+	EnableCache(cfg)
+	require.NotNil(t, config.Client, "LRU client must be set")
+	ta.True(t, IsCacheInitialized())
+
+	// Verify basic ops work with LRU client.
+	CacheStore("lru-key", []byte("lru-val"))
+	got := CacheLookup("lru-key")
+	ta.Equal(t, []byte("lru-val"), got)
+}
+
+// TestEnableCache_NilLogger covers the auto-logger creation branch.
+func TestEnableCache_NilLogger_AutoCreatesLogger(t *testing.T) {
+	prev := config
+	prevStats := cacheStats
+	defer func() {
+		config = prev
+		cacheStats = prevStats
+	}()
+
+	cfg := &CacheConfig{
+		Logger: nil, // deliberately nil
+		TTL:    5,
+	}
+	// Should not panic; logger is created internally.
+	ta.NotPanics(t, func() { EnableCache(cfg) })
+	ta.NotNil(t, cfg.Logger)
+}
+
+// TestEnableCache_MemoryDefaults covers the default memory sizing branch (maxMemory<=0).
+func TestEnableCache_MemoryDefaults_UsesDefaultSizes(t *testing.T) {
+	prev := config
+	prevStats := cacheStats
+	defer func() {
+		config = prev
+		cacheStats = prevStats
+	}()
+
+	cfg := &CacheConfig{
+		Logger: libpack_logger.New(),
+		TTL:    5,
+	}
+	// MaxMemorySize and MaxEntries left at zero → defaults kick in.
+	EnableCache(cfg)
+	require.NotNil(t, config.Client)
+	ta.Greater(t, GetCacheMaxMemorySize(), int64(0))
+}
+
+// TestEnableCache_RedisFallback covers the Redis error → memory fallback branch.
+func TestEnableCache_RedisFallback_FallsBackToMemory(t *testing.T) {
+	prev := config
+	prevStats := cacheStats
+	defer func() {
+		config = prev
+		cacheStats = prevStats
+	}()
+
+	cfg := &CacheConfig{
+		Logger: libpack_logger.New(),
+		TTL:    5,
+	}
+	cfg.Redis.Enable = true
+	cfg.Redis.URL = "127.0.0.1:1" // unreachable port → connection error
+	cfg.Redis.DB = 0
+
+	// Must not panic; should fall back to memory.
+	ta.NotPanics(t, func() { EnableCache(cfg) })
+	require.NotNil(t, config.Client, "fallback memory client must be set")
+
+	// Verify it actually works as a memory cache.
+	CacheStore("fallback-key", []byte("fallback-val"))
+	got := CacheLookup("fallback-key")
+	ta.Equal(t, []byte("fallback-val"), got)
+}
+
+// TestCacheStore_Uninitialized covers the early-return + log branch in CacheStore (line 238-242).
+func TestCacheStore_Uninitialized_DoesNotPanic(t *testing.T) {
+	prev := config
+	config = &CacheConfig{
+		Logger: libpack_logger.New(),
+		Client: nil, // IsCacheInitialized() returns false
+	}
+	defer func() { config = prev }()
+
+	ta.NotPanics(t, func() {
+		CacheStore("any-key", []byte("any-val"))
+	})
+}
+
+// TestCacheClear_Uninitialized covers the early-return in CacheClear.
+func TestCacheClear_Uninitialized_DoesNotPanic(t *testing.T) {
+	prev := config
+	config = nil
+	defer func() { config = prev }()
+
+	ta.NotPanics(t, func() { CacheClear() })
+}
+
+// TestCacheDelete_ZeroStats covers the CAS loop branch where CachedQueries is already 0.
+func TestCacheDelete_ZeroStats_DoesNotDecrementBelowZero(t *testing.T) {
+	defer withFreshMemoryCache(t, 5*time.Minute)()
+	cacheStats.CachedQueries = 0 // already at zero
+
+	// Should not panic and stats should stay at 0.
+	CacheDelete("nonexistent-key")
+	ta.Equal(t, int64(0), cacheStats.CachedQueries)
+}
+
+// TestEnableCache_Redis_HappyPath covers successful Redis init via miniredis.
+func TestEnableCache_Redis_HappyPath_StoresAndRetrieves(t *testing.T) {
+	mr, err := miniredis.Run()
+	require.NoError(t, err)
+	defer mr.Close()
+
+	prev := config
+	prevStats := cacheStats
+	defer func() {
+		config = prev
+		cacheStats = prevStats
+	}()
+
+	cfg := &CacheConfig{
+		Logger: libpack_logger.New(),
+		TTL:    5,
+	}
+	cfg.Redis.Enable = true
+	cfg.Redis.URL = mr.Addr()
+	cfg.Redis.DB = 0
+	EnableCache(cfg)
+
+	require.True(t, IsCacheInitialized())
+	CacheStore("r-key", []byte("r-val"))
+	ta.Equal(t, []byte("r-val"), CacheLookup("r-key"))
+
+	// GetCacheMemoryUsage and GetCacheMaxMemorySize via Redis wrapper.
+	ta.GreaterOrEqual(t, GetCacheMemoryUsage(), int64(0))
+	ta.GreaterOrEqual(t, GetCacheMaxMemorySize(), int64(0))
+}
@@ -52,13 +52,9 @@ func NewLRUMemoryCache(maxMemorySize, maxEntries int64) *LRUMemoryCache {

 // Set adds or updates an entry in the cache
 func (c *LRUMemoryCache) Set(key string, value []byte, ttl time.Duration) {
-	c.mu.Lock()
-	defer c.mu.Unlock()
-
-	// Calculate expiry time
-	expiresAt := time.Now().Add(ttl)
-
-	// Check if we should compress
+	// Compress OUTSIDE the lock — gzip is CPU-bound and pool ops are
+	// goroutine-safe. Result is just a byte slice, safe to hand to the
+	// critical section below.
 	compressed := false
 	finalValue := value
 	if len(value) > 1024 { // Compress if larger than 1KB
@@ -69,6 +65,10 @@ func (c *LRUMemoryCache) Set(key string, value []byte, ttl time.Duration) {
 	}

 	entrySize := int64(len(key) + len(finalValue) + 64) // 64 bytes overhead estimate
+	expiresAt := time.Now().Add(ttl)
+
+	c.mu.Lock()
+	defer c.mu.Unlock()

 	// Check if key exists
 	if existing, exists := c.entries[key]; exists {
@@ -107,34 +107,49 @@ func (c *LRUMemoryCache) Set(key string, value []byte, ttl time.Duration) {

 // Get retrieves a value from the cache
 func (c *LRUMemoryCache) Get(key string) ([]byte, bool) {
+	// Snapshot the stored bytes under the lock, then release before
+	// decompressing — gzip is CPU-bound and must not serialise other ops.
 	c.mu.Lock()
-	defer c.mu.Unlock()
-
 	entry, exists := c.entries[key]
 	if !exists {
+		c.mu.Unlock()
 		return nil, false
 	}

-	// Check if expired
+	// Check if expired (must use the entry's stored expiry while locked)
 	if time.Now().After(entry.expiresAt) {
 		c.removeEntry(entry)
+		c.mu.Unlock()
 		return nil, false
 	}

 	// Move to front (most recently used)
 	c.evictList.MoveToFront(entry.element)

-	// Decompress if needed
-	if entry.compressed {
-		if decompressed, err := c.decompress(entry.value); err == nil {
-			return decompressed, true
-		}
-		// If decompression fails, remove the entry
-		c.removeEntry(entry)
-		return nil, false
+	if !entry.compressed {
+		// Uncompressed payload is immutable once stored, safe to return directly.
+		value := entry.value
+		c.mu.Unlock()
+		return value, true
 	}

-	return entry.value, true
+	// Snapshot compressed bytes locally, drop lock, then decompress.
+	compressedBytes := entry.value
+	c.mu.Unlock()
+
+	decompressed, err := c.decompress(compressedBytes)
+	if err == nil {
+		return decompressed, true
+	}
+
+	// Decompression failed — re-acquire lock to remove the bad entry,
+	// but only if it still exists and still points at the same payload.
+	c.mu.Lock()
+	if cur, ok := c.entries[key]; ok && cur == entry {
+		c.removeEntry(cur)
+	}
+	c.mu.Unlock()
+	return nil, false
 }

 // Delete removes an entry from the cache
@@ -0,0 +1,334 @@
+package libpack_cache_redis
+
+import (
+	"testing"
+	"time"
+
+	"github.com/alicebob/miniredis/v2"
+	libpack_logger "github.com/lukaszraczylo/graphql-monitoring-proxy/logging"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// ---------------------------------------------------------------------------
+// helpers
+// ---------------------------------------------------------------------------
+
+func newTestRedis(t *testing.T) (*RedisConfig, *miniredis.Miniredis) {
+	t.Helper()
+	s, err := miniredis.Run()
+	require.NoError(t, err)
+	t.Cleanup(s.Close)
+
+	rc, err := New(&RedisClientConfig{
+		RedisServer: s.Addr(),
+		Prefix:      "pfx:",
+	})
+	require.NoError(t, err)
+	return rc, s
+}
+
+func newTestWrapper(t *testing.T) (*CacheWrapper, *miniredis.Miniredis) {
+	t.Helper()
+	rc, s := newTestRedis(t)
+	w := NewCacheWrapper(rc, libpack_logger.New())
+	return w, s
+}
+
+// ---------------------------------------------------------------------------
+// New — connection failure path
+// ---------------------------------------------------------------------------
+
+func TestNew_ConnectionFailure_ReturnsError(t *testing.T) {
+	t.Parallel()
+	_, err := New(&RedisClientConfig{
+		RedisServer: "127.0.0.1:1", // nothing listens here
+	})
+	assert.Error(t, err)
+}
+
+// ---------------------------------------------------------------------------
+// redis.go — GetMemoryUsage
+// ---------------------------------------------------------------------------
+
+func TestGetMemoryUsage_ConnectedServer_ReturnsZero(t *testing.T) {
+	t.Parallel()
+	rc, _ := newTestRedis(t)
+	got := rc.GetMemoryUsage()
+	// Implementation always returns 0 as a placeholder; assert the contract.
+	assert.Equal(t, int64(0), got)
+}
+
+func TestGetMemoryUsage_ClosedServer_ReturnsZero(t *testing.T) {
+	t.Parallel()
+	rc, s := newTestRedis(t)
+	s.Close() // simulate disconnection before cleanup fires
+	got := rc.GetMemoryUsage()
+	assert.Equal(t, int64(0), got)
+}
+
+// ---------------------------------------------------------------------------
+// redis.go — GetMaxMemorySize
+// ---------------------------------------------------------------------------
+
+func TestGetMaxMemorySize_AlwaysZero(t *testing.T) {
+	t.Parallel()
+	rc, _ := newTestRedis(t)
+	assert.Equal(t, int64(0), rc.GetMaxMemorySize())
+}
+
+// ---------------------------------------------------------------------------
+// redis.go — Get error path (closed server)
+// ---------------------------------------------------------------------------
+
+func TestGet_ClosedServer_ReturnsError(t *testing.T) {
+	t.Parallel()
+	rc, s := newTestRedis(t)
+	// Set a key while server is up, then close.
+	require.NoError(t, rc.Set("k", []byte("v"), 0))
+	s.Close()
+
+	_, found, err := rc.Get("k")
+	assert.Error(t, err)
+	assert.False(t, found)
+}
+
+// ---------------------------------------------------------------------------
+// redis.go — CountQueries error path
+// ---------------------------------------------------------------------------
+
+func TestCountQueries_ClosedServer_ReturnsError(t *testing.T) {
+	t.Parallel()
+	rc, s := newTestRedis(t)
+	s.Close()
+
+	count, err := rc.CountQueries()
+	assert.Error(t, err)
+	assert.Equal(t, int64(0), count)
+}
+
+// ---------------------------------------------------------------------------
+// redis.go — CountQueriesWithPattern error path
+// ---------------------------------------------------------------------------
+
+func TestCountQueriesWithPattern_ClosedServer_ReturnsError(t *testing.T) {
+	t.Parallel()
+	rc, s := newTestRedis(t)
+	s.Close()
+
+	count, err := rc.CountQueriesWithPattern("*")
+	assert.Error(t, err)
+	assert.Equal(t, 0, count)
+}
+
+// ---------------------------------------------------------------------------
+// redis.go — TTL=0 (no expiry) vs expired key
+// ---------------------------------------------------------------------------
+
+func TestGet_MissingKey_ReturnsFalseNoError(t *testing.T) {
+	t.Parallel()
+	rc, _ := newTestRedis(t)
+	val, found, err := rc.Get("nonexistent-key-xyz")
+	assert.NoError(t, err)
+	assert.False(t, found)
+	assert.Nil(t, val)
+}
+
+func TestSet_TTLZero_KeyPersists(t *testing.T) {
+	t.Parallel()
+	rc, s := newTestRedis(t)
+	require.NoError(t, rc.Set("persist", []byte("yes"), 0))
+	s.FastForward(24 * time.Hour)
+	_, found, err := rc.Get("persist")
+	assert.NoError(t, err)
+	assert.True(t, found)
+}
+
+func TestSet_WithTTL_KeyExpires(t *testing.T) {
+	t.Parallel()
+	rc, s := newTestRedis(t)
+	require.NoError(t, rc.Set("expires", []byte("yes"), 1*time.Second))
+	s.FastForward(2 * time.Second)
+	_, found, err := rc.Get("expires")
+	assert.NoError(t, err)
+	assert.False(t, found)
+}
+
+// ---------------------------------------------------------------------------
+// redis.go — large value round-trip
+// ---------------------------------------------------------------------------
+
+func TestSet_LargeValue_RoundTrip(t *testing.T) {
+	t.Parallel()
+	rc, _ := newTestRedis(t)
+	large := make([]byte, 1<<16) // 64 KB
+	for i := range large {
+		large[i] = byte(i % 251)
+	}
+	require.NoError(t, rc.Set("big", large, 0))
+	got, found, err := rc.Get("big")
+	assert.NoError(t, err)
+	assert.True(t, found)
+	assert.Equal(t, large, got)
+}
+
+// ---------------------------------------------------------------------------
+// redis.go — prefix isolation
+// ---------------------------------------------------------------------------
+
+func TestPrerendKeyName_PrefixIsolation(t *testing.T) {
+	t.Parallel()
+	s, err := miniredis.Run()
+	require.NoError(t, err)
+	defer s.Close()
+
+	rc1, err := New(&RedisClientConfig{RedisServer: s.Addr(), Prefix: "a:"})
+	require.NoError(t, err)
+	rc2, err := New(&RedisClientConfig{RedisServer: s.Addr(), Prefix: "b:"})
+	require.NoError(t, err)
+
+	require.NoError(t, rc1.Set("key", []byte("one"), 0))
+	require.NoError(t, rc2.Set("key", []byte("two"), 0))
+
+	v1, ok1, err1 := rc1.Get("key")
+	assert.NoError(t, err1)
+	assert.True(t, ok1)
+	assert.Equal(t, []byte("one"), v1)
+
+	v2, ok2, err2 := rc2.Get("key")
+	assert.NoError(t, err2)
+	assert.True(t, ok2)
+	assert.Equal(t, []byte("two"), v2)
+}
+
+// ---------------------------------------------------------------------------
+// wrapper.go — NewCacheWrapper with explicit logger
+// ---------------------------------------------------------------------------
+
+func TestNewCacheWrapper_WithLogger_UsesIt(t *testing.T) {
+	t.Parallel()
+	rc, _ := newTestRedis(t)
+	logger := &libpack_logger.Logger{}
+	w := NewCacheWrapper(rc, logger)
+	assert.NotNil(t, w)
+}
+
+func TestNewCacheWrapper_NilLogger_DoesNotPanic(t *testing.T) {
+	t.Parallel()
+	rc, _ := newTestRedis(t)
+	// NewCacheWrapper substitutes a zero-value Logger when nil is passed.
+	// Only verify construction succeeds; don't exercise error paths through
+	// this wrapper because zero-value Logger.output is nil and would panic.
+	w := NewCacheWrapper(rc, nil)
+	assert.NotNil(t, w)
+	// Happy-path operations are safe even with the zero-value logger.
+	w.Set("probe", []byte("ok"), 0)
+	got, found := w.Get("probe")
+	assert.True(t, found)
+	assert.Equal(t, []byte("ok"), got)
+}
+
+// ---------------------------------------------------------------------------
+// wrapper.go — Set / Get / Delete / Clear happy paths
+// ---------------------------------------------------------------------------
+
+func TestWrapper_SetAndGet_HappyPath(t *testing.T) {
+	t.Parallel()
+	w, _ := newTestWrapper(t)
+	w.Set("wkey", []byte("wval"), 0)
+	got, found := w.Get("wkey")
+	assert.True(t, found)
+	assert.Equal(t, []byte("wval"), got)
+}
+
+func TestWrapper_Get_MissingKey_ReturnsFalse(t *testing.T) {
+	t.Parallel()
+	w, _ := newTestWrapper(t)
+	val, found := w.Get("ghost")
+	assert.False(t, found)
+	assert.Nil(t, val)
+}
+
+func TestWrapper_Delete_RemovesKey(t *testing.T) {
+	t.Parallel()
+	w, _ := newTestWrapper(t)
+	w.Set("del", []byte("gone"), 0)
+	w.Delete("del")
+	_, found := w.Get("del")
+	assert.False(t, found)
+}
+
+func TestWrapper_Clear_RemovesAllKeys(t *testing.T) {
+	t.Parallel()
+	w, _ := newTestWrapper(t)
+	w.Set("a", []byte("1"), 0)
+	w.Set("b", []byte("2"), 0)
+	w.Clear()
+	assert.Equal(t, int64(0), w.CountQueries())
+}
+
+func TestWrapper_CountQueries_ReturnsCount(t *testing.T) {
+	t.Parallel()
+	w, _ := newTestWrapper(t)
+	w.Set("c1", []byte("x"), 0)
+	w.Set("c2", []byte("y"), 0)
+	assert.Equal(t, int64(2), w.CountQueries())
+}
+
+// ---------------------------------------------------------------------------
+// wrapper.go — GetMemoryUsage / GetMaxMemorySize always 0
+// ---------------------------------------------------------------------------
+
+func TestWrapper_GetMemoryUsage_AlwaysZero(t *testing.T) {
+	t.Parallel()
+	w, _ := newTestWrapper(t)
+	assert.Equal(t, int64(0), w.GetMemoryUsage())
+}
+
+func TestWrapper_GetMaxMemorySize_AlwaysZero(t *testing.T) {
+	t.Parallel()
+	w, _ := newTestWrapper(t)
+	assert.Equal(t, int64(0), w.GetMaxMemorySize())
+}
+
+// ---------------------------------------------------------------------------
+// wrapper.go — error paths via closed server (logs, doesn't panic)
+// ---------------------------------------------------------------------------
+
+func TestWrapper_Set_ClosedServer_LogsError(t *testing.T) {
+	t.Parallel()
+	w, s := newTestWrapper(t)
+	s.Close()
+	// Must not panic; error is swallowed and logged.
+	w.Set("k", []byte("v"), 0)
+}
+
+func TestWrapper_Get_ClosedServer_ReturnsFalse(t *testing.T) {
+	t.Parallel()
+	w, s := newTestWrapper(t)
+	s.Close()
+	val, found := w.Get("k")
+	assert.False(t, found)
+	assert.Nil(t, val)
+}
+
+func TestWrapper_Delete_ClosedServer_LogsError(t *testing.T) {
+	t.Parallel()
+	w, s := newTestWrapper(t)
+	s.Close()
+	w.Delete("k") // must not panic
+}
+
+func TestWrapper_Clear_ClosedServer_LogsError(t *testing.T) {
+	t.Parallel()
+	w, s := newTestWrapper(t)
+	s.Close()
+	w.Clear() // must not panic
+}
+
+func TestWrapper_CountQueries_ClosedServer_ReturnsZero(t *testing.T) {
+	t.Parallel()
+	w, s := newTestWrapper(t)
+	s.Close()
+	assert.Equal(t, int64(0), w.CountQueries())
+}