feat: add cache, outbound HTTP, request protection, tasks and module scaffolding

cache/cache_test.go

@@ -0,0 +1,118 @@
+package cache
+
+import (
+	"context"
+	"errors"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+func TestMemoryOwnershipCapacityExpiryAndClose(t *testing.T) {
+	m, err := NewMemory(MemoryConfig{MaxEntries: 2, MaxBytes: 10})
+	if err != nil {
+		t.Fatal(err)
+	}
+	now := time.Now()
+	m.now = func() time.Time { return now }
+	ctx := context.Background()
+	value := []byte("aa")
+	if err := m.Set(ctx, "a", value, time.Second); err != nil {
+		t.Fatal(err)
+	}
+	value[0] = 'x'
+	got, _ := m.Get(ctx, "a")
+	if string(got) != "aa" {
+		t.Fatal("retained caller memory")
+	}
+	got[0] = 'z'
+	got, _ = m.Get(ctx, "a")
+	if string(got) != "aa" {
+		t.Fatal("returned mutable cache memory")
+	}
+	m.Set(ctx, "b", []byte("bb"), 0)
+	m.Get(ctx, "a")
+	m.Set(ctx, "c", []byte("cc"), 0)
+	if _, err := m.Get(ctx, "b"); !errors.Is(err, ErrMiss) {
+		t.Fatal("LRU eviction failed")
+	}
+	now = now.Add(time.Second)
+	if _, err := m.Get(ctx, "a"); !errors.Is(err, ErrMiss) {
+		t.Fatal("expiration boundary ignored")
+	}
+	if err := m.Set(ctx, "large", []byte("123456"), 0); !errors.Is(err, ErrTooLarge) {
+		t.Fatal(err)
+	}
+	if _, err := m.Get(ctx, "c"); err != nil {
+		t.Fatal("oversized write evicted valid data")
+	}
+	canceled, cancel := context.WithCancel(ctx)
+	cancel()
+	if err := m.Delete(canceled, "c"); !errors.Is(err, context.Canceled) {
+		t.Fatal(err)
+	}
+	m.Close()
+	m.Close()
+	if _, err := m.Get(ctx, "c"); !errors.Is(err, ErrClosed) {
+		t.Fatal(err)
+	}
+}
+
+func TestLoaderCoalescesAndSeparatesCallerCancellation(t *testing.T) {
+	m, _ := NewMemory(MemoryConfig{})
+	loader, _ := NewLoader(m, LoaderConfig{MaxLoads: 1, Timeout: time.Second})
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	started, release := make(chan struct{}), make(chan struct{})
+	var calls atomic.Int32
+	load := func(ctx context.Context) ([]byte, error) {
+		calls.Add(1)
+		close(started)
+		select {
+		case <-release:
+			return []byte("value"), nil
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		}
+	}
+	first := make(chan error, 1)
+	go func() { _, err := loader.GetOrLoad(ctx, "key", time.Minute, load); first <- err }()
+	<-started
+	second := make(chan error, 1)
+	go func() {
+		v, err := loader.GetOrLoad(context.Background(), "key", time.Minute, load)
+		if err == nil && string(v) != "value" {
+			err = errors.New("wrong value")
+		}
+		second <- err
+	}()
+	if _, err := loader.GetOrLoad(context.Background(), "other", 0, load); !errors.Is(err, ErrBusy) {
+		t.Fatal(err)
+	}
+	cancel()
+	if err := <-first; !errors.Is(err, context.Canceled) {
+		t.Fatal(err)
+	}
+	close(release)
+	if err := <-second; err != nil {
+		t.Fatal(err)
+	}
+	if calls.Load() != 1 {
+		t.Fatalf("loads=%d", calls.Load())
+	}
+}
+
+func TestLoaderPanicDeadlineAndStoreFailure(t *testing.T) {
+	m, _ := NewMemory(MemoryConfig{})
+	l, _ := NewLoader(m, LoaderConfig{Timeout: 20 * time.Millisecond})
+	if _, err := l.GetOrLoad(context.Background(), "panic", 0, func(context.Context) ([]byte, error) { panic("failure") }); err == nil {
+		t.Fatal("panic escaped")
+	}
+	if _, err := l.GetOrLoad(context.Background(), "panic", 0, func(ctx context.Context) ([]byte, error) { <-ctx.Done(); return nil, ctx.Err() }); !errors.Is(err, context.DeadlineExceeded) {
+		t.Fatal(err)
+	}
+	m.Close()
+	if _, err := l.GetOrLoad(context.Background(), "closed", 0, func(context.Context) ([]byte, error) { t.Fatal("store outage triggered load"); return nil, nil }); !errors.Is(err, ErrClosed) {
+		t.Fatal(err)
+	}
+}