refactor(backend): extract to pkg/cap

pkg/diskcache/cache_test.go

@@ -0,0 +1,212 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package diskcache
+
+import (
+	"bytes"
+	"os"
+	"testing"
+	"time"
+)
+
+func TestDiskCacheBasic(t *testing.T) {
+	testDir := "uploads/test_diskcache_basic"
+	defer func() { _ = os.RemoveAll(testDir) }()
+	_ = os.RemoveAll(testDir)
+
+	c := New(testDir)
+	defer func() { _ = c.Clear() }()
+
+	key := "key1"
+	val := []byte("value1")
+
+	// Get non-existent
+	_, err := c.Get(key)
+	if err != ErrCacheMiss {
+		t.Fatalf("expected ErrCacheMiss, got %v", err)
+	}
+
+	// Set & Get
+	err = c.Set(key, val, 10*time.Second)
+	if err != nil {
+		t.Fatalf("failed to set cache: %v", err)
+	}
+
+	got, err := c.Get(key)
+	if err != nil {
+		t.Fatalf("failed to get cache: %v", err)
+	}
+
+	if !bytes.Equal(got, val) {
+		t.Errorf("expected %s, got %s", val, got)
+	}
+
+	// Delete
+	err = c.Delete(key)
+	if err != nil {
+		t.Fatalf("failed to delete: %v", err)
+	}
+
+	_, err = c.Get(key)
+	if err != ErrCacheMiss {
+		t.Errorf("expected ErrCacheMiss after delete, got %v", err)
+	}
+}
+
+func TestDiskCacheTTL(t *testing.T) {
+	testDir := "uploads/test_diskcache_ttl"
+	defer func() { _ = os.RemoveAll(testDir) }()
+	_ = os.RemoveAll(testDir)
+
+	c := New(testDir)
+	defer func() { _ = c.Clear() }()
+
+	key := "ttlkey"
+	val := []byte("ttlval")
+
+	// Set with 200ms TTL
+	err := c.Set(key, val, 200*time.Millisecond)
+	if err != nil {
+		t.Fatalf("failed to set: %v", err)
+	}
+
+	// Immediate Get should succeed
+	got, err := c.Get(key)
+	if err != nil {
+		t.Fatalf("failed to get: %v", err)
+	}
+	if !bytes.Equal(got, val) {
+		t.Errorf("expected %s, got %s", val, got)
+	}
+
+	// Sleep 250ms to expire
+	time.Sleep(250 * time.Millisecond)
+
+	// Get should fail with cache miss
+	_, err = c.Get(key)
+	if err != ErrCacheMiss {
+		t.Errorf("expected ErrCacheMiss after TTL expiration, got %v", err)
+	}
+}
+
+func TestDiskCacheExpirationPolicies(t *testing.T) {
+	testDir := "uploads/test_diskcache_expiration_policies"
+	defer func() { _ = os.RemoveAll(testDir) }()
+	_ = os.RemoveAll(testDir)
+
+	c := New(testDir)
+	defer func() { _ = c.Clear() }()
+	c.defaultTTL = 50 * time.Millisecond
+
+	if err := c.Set("default", []byte("default"), DefaultExpiration); err != nil {
+		t.Fatalf("Set(default, DefaultExpiration) returned error: %v", err)
+	}
+	if err := c.Set("custom", []byte("custom"), 100*time.Millisecond); err != nil {
+		t.Fatalf("Set(custom, 100ms) returned error: %v", err)
+	}
+	if err := c.Set("permanent", []byte("permanent"), NoExpiration); err != nil {
+		t.Fatalf("Set(permanent, NoExpiration) returned error: %v", err)
+	}
+
+	time.Sleep(75 * time.Millisecond)
+
+	if _, err := c.Get("default"); err != ErrCacheMiss {
+		t.Errorf("Get(default) error = %v, want ErrCacheMiss", err)
+	}
+	if _, err := c.Get("custom"); err != nil {
+		t.Errorf("Get(custom) returned error before custom TTL elapsed: %v", err)
+	}
+	if _, err := c.Get("permanent"); err != nil {
+		t.Errorf("Get(permanent) returned error: %v", err)
+	}
+
+	time.Sleep(50 * time.Millisecond)
+
+	if _, err := c.Get("custom"); err != ErrCacheMiss {
+		t.Errorf("Get(custom) error = %v, want ErrCacheMiss", err)
+	}
+	if _, err := c.Get("permanent"); err != nil {
+		t.Errorf("Get(permanent) returned error after other entries expired: %v", err)
+	}
+}
+
+func TestDiskCacheNoExpirationSurvivesReload(t *testing.T) {
+	testDir := "uploads/test_diskcache_no_expiration_reload"
+	defer func() { _ = os.RemoveAll(testDir) }()
+	_ = os.RemoveAll(testDir)
+
+	c := New(testDir)
+	if err := c.Set("permanent", []byte("value"), NoExpiration); err != nil {
+		t.Fatalf("Set(permanent, NoExpiration) returned error: %v", err)
+	}
+
+	reloaded := New(testDir)
+	defer func() { _ = reloaded.Clear() }()
+
+	got, err := reloaded.Get("permanent")
+	if err != nil {
+		t.Fatalf("reloaded Get(permanent) returned error: %v", err)
+	}
+	if !bytes.Equal(got, []byte("value")) {
+		t.Errorf("reloaded Get(permanent) = %q, want %q", got, "value")
+	}
+}
+
+func TestDiskCacheLRUEviction(t *testing.T) {
+	testDir := "uploads/test_diskcache_lru"
+	defer func() { _ = os.RemoveAll(testDir) }()
+	_ = os.RemoveAll(testDir)
+
+	c := New(testDir)
+	defer func() { _ = c.Clear() }()
+
+	// Force a very small max size of 20 bytes for testing (8 bytes header + payload)
+	// So 2 items of 2 bytes payload = 2 * (8 + 2) = 20 bytes max.
+	c.maxSize = 20
+	c.lruEnabled = true
+
+	// Write item 1: 8 + 2 = 10 bytes
+	err := c.Set("k1", []byte("v1"), DefaultExpiration)
+	if err != nil {
+		t.Fatalf("failed to set k1: %v", err)
+	}
+
+	// Write item 2: 8 + 2 = 10 bytes
+	err = c.Set("k2", []byte("v2"), DefaultExpiration)
+	if err != nil {
+		t.Fatalf("failed to set k2: %v", err)
+	}
+
+	// Both should exist
+	if _, err := c.Get("k1"); err != nil {
+		t.Errorf("k1 should exist: %v", err)
+	}
+	if _, err := c.Get("k2"); err != nil {
+		t.Errorf("k2 should exist: %v", err)
+	}
+
+	// Write item 3: 8 + 2 = 10 bytes -> total size would be 30, exceeding 20.
+	// This should evict the oldest item. Since k1 was accessed, but then k2 was accessed,
+	// wait, let's access k1 again to make it the most recently used, so k2 becomes oldest!
+	_, _ = c.Get("k1") // k1 is now MRU, k2 is LRU
+
+	err = c.Set("k3", []byte("v3"), DefaultExpiration)
+	if err != nil {
+		t.Fatalf("failed to set k3: %v", err)
+	}
+
+	// k2 should be evicted, k1 and k3 should exist
+	_, err = c.Get("k2")
+	if err != ErrCacheMiss {
+		t.Errorf("expected k2 to be evicted, got error %v", err)
+	}
+
+	if _, err := c.Get("k1"); err != nil {
+		t.Errorf("k1 should still exist: %v", err)
+	}
+
+	if _, err := c.Get("k3"); err != nil {
+		t.Errorf("k3 should exist: %v", err)
+	}
+}