internal/lru: Add sharded CLOCK

1 files changed, 100 insertions, 0 deletions

diff --git a/internal/clock/cache_test.go b/internal/clock/cache_test.go
new file mode 100644
index 00000000..116efdd3
--- /dev/null
+++ b/internal/clock/cache_test.go
@@ -0,0 +1,100 @@
+package clock_test
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"lindenii.org/go/furgit/internal/clock"
+	"lindenii.org/go/lgo/intconv"
+)
+
+func byteWeight(_ string, value string) uint64 {
+	weight, err := intconv.IntToUint64(len(value))
+	if err != nil {
+		return 0
+	}
+
+	return weight
+}
+
+func TestCacheAddGetPeek(t *testing.T) {
+	t.Parallel()
+
+	cache := clock.New(1<<20, byteWeight)
+
+	if !cache.Add("a", "alpha") {
+		t.Fatalf("Add(a) should succeed")
+	}
+
+	if got, ok := cache.Get("a"); !ok || got != "alpha" {
+		t.Fatalf("Get(a) = (%q, %v), want (alpha, true)", got, ok)
+	}
+
+	if got, ok := cache.Peek("a"); !ok || got != "alpha" {
+		t.Fatalf("Peek(a) = (%q, %v), want (alpha, true)", got, ok)
+	}
+
+	if _, ok := cache.Get("missing"); ok {
+		t.Fatalf("Get(missing) should miss")
+	}
+}
+
+func TestCacheWeightStaysBounded(t *testing.T) {
+	t.Parallel()
+
+	const maxWeight = 4096
+
+	cache := clock.New(maxWeight, byteWeight)
+	value := strings.Repeat("x", 64)
+
+	for i := range 1000 {
+		cache.Add(fmt.Sprintf("key-%d", i), value)
+	}
+
+	if got := cache.Weight(); got > maxWeight {
+		t.Fatalf("weight = %d, exceeds max %d", got, maxWeight)
+	}
+}
+
+func TestCacheLenAndClear(t *testing.T) {
+	t.Parallel()
+
+	cache := clock.New(1<<20, byteWeight)
+
+	for i := range 10 {
+		cache.Add(fmt.Sprintf("key-%d", i), "v")
+	}
+
+	if got := cache.Len(); got != 10 {
+		t.Fatalf("Len = %d, want 10", got)
+	}
+
+	cache.Clear()
+
+	if got := cache.Len(); got != 0 {
+		t.Fatalf("Len after Clear = %d, want 0", got)
+	}
+
+	if got := cache.Weight(); got != 0 {
+		t.Fatalf("Weight after Clear = %d, want 0", got)
+	}
+}
+
+func TestCacheRejectsOversized(t *testing.T) {
+	t.Parallel()
+
+	cache := clock.New(4, byteWeight)
+
+	if cache.Add("a", "xxxxx") {
+		t.Fatalf("oversized Add should report false")
+	}
+
+	if _, ok := cache.Get("a"); ok {
+		t.Fatalf("oversized entry must not be cached")
+	}
+
+	if got := cache.Weight(); got != 0 {
+		t.Fatalf("weight = %d, want 0", got)
+	}
+}