fix: align slice/set equality and harden queue API

queue.go

@@ -6,6 +6,7 @@ import (
 )
 
 var QueueFullErr = errors.New("queue full")
+var QueueEmptyErr = errors.New("queue empty")
 
 type Queue[T any] struct {
 	size  uint64
@@ -27,37 +28,48 @@ func (q *Queue[T]) IsFull() bool  { return q.Len() == q.size }
 func (q *Queue[T]) Size() uint64  { return q.size }
 
 func (q *Queue[T]) Enqueue(el T) error {
-	if q.IsFull() {
+	q.mu.Lock()
+	defer q.mu.Unlock()
+
+	if uint64(len(q.queue)) == q.size {
 		return QueueFullErr
 	}
 	q.queue = q.queue.Push(el)
 	return nil
 }
 
-func (q *Queue[T]) Dequeue() T {
-	q.mu.RLock()
-	el := q.queue.Get(0)
-	q.mu.RUnlock()
+func (q *Queue[T]) Dequeue() (T, error) {
+	q.mu.Lock()
+	defer q.mu.Unlock()
 
-	if q.Len() == 1 {
-		q.mu.Lock()
-		q.queue = make(Slice[T], 0)
-		q.mu.Unlock()
-		return el
+	var zero T
+	if len(q.queue) == 0 {
+		return zero, QueueEmptyErr
 	}
 
-	q.mu.Lock()
-	q.queue = q.queue.Pop(0)
-	q.mu.Unlock()
-	return el
+	el := q.queue[0]
+	copy(q.queue, q.queue[1:])
+	q.queue[len(q.queue)-1] = zero
+	q.queue = q.queue[:len(q.queue)-1]
+
+	return el, nil
 }
 
-func (q *Queue[T]) Peak() T {
+func (q *Queue[T]) Peak() (T, error) {
 	q.mu.RLock()
 	defer q.mu.RUnlock()
-	return q.queue.Get(0)
+
+	var zero T
+	if len(q.queue) == 0 {
+		return zero, QueueEmptyErr
+	}
+
+	return q.queue[0], nil
 }
 
 func (q *Queue[T]) Raw() Slice[T] {
-	return q.queue
+	q.mu.RLock()
+	defer q.mu.RUnlock()
+
+	return NewSliceFrom(q.queue)
 }

queue_test.go

@@ -11,14 +11,19 @@ func ExampleCreateQueue() {
 	if err != nil {
 		panic(err)
 	}
-	i := q.Dequeue() // <- Here we got 1
+	i, err := q.Dequeue() // <- Here we got 1
+	if err != nil {
+		panic(err)
+	}
 	log.Println(i)
 }
 func BenchmarkQueue_Enqueue(b *testing.B) {
 	b.StartTimer()
 	q := CreateQueue[int](uint64(b.N))
 	for i := 0; i < b.N; i++ {
-		q.Enqueue(i)
+		if err := q.Enqueue(i); err != nil {
+			b.Fatal(err)
+		}
 	}
 	b.StopTimer()
 	b.ReportAllocs()
@@ -26,11 +31,15 @@ func BenchmarkQueue_Enqueue(b *testing.B) {
 func BenchmarkQueue_Dequeue(b *testing.B) {
 	q := CreateQueue[int](uint64(b.N))
 	for i := 0; i < b.N; i++ {
-		q.Enqueue(i)
+		if err := q.Enqueue(i); err != nil {
+			b.Fatal(err)
+		}
 	}
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
-		q.Dequeue()
+		if _, err := q.Dequeue(); err != nil {
+			b.Fatal(err)
+		}
 	}
 	b.StopTimer()
 	b.ReportAllocs()
@@ -39,11 +48,82 @@ func BenchmarkQueue_EnqueueDequeue(b *testing.B) {
 	b.StartTimer()
 	q := CreateQueue[int](uint64(b.N))
 	for i := 0; i < b.N; i++ {
-		q.Enqueue(i)
+		if err := q.Enqueue(i); err != nil {
+			b.Fatal(err)
+		}
 	}
 	for i := 0; i < b.N; i++ {
-		q.Dequeue()
+		if _, err := q.Dequeue(); err != nil {
+			b.Fatal(err)
+		}
 	}
 	b.StopTimer()
 	b.ReportAllocs()
 }
+
+func TestQueue_Empty(t *testing.T) {
+	q := CreateQueue[int](1)
+
+	if _, err := q.Peak(); err != QueueEmptyErr {
+		t.Fatalf("Peak() error = %v, want %v", err, QueueEmptyErr)
+	}
+	if _, err := q.Dequeue(); err != QueueEmptyErr {
+		t.Fatalf("Dequeue() error = %v, want %v", err, QueueEmptyErr)
+	}
+}
+
+func TestQueue_BasicOperations(t *testing.T) {
+	q := CreateQueue[int](2)
+
+	if err := q.Enqueue(1); err != nil {
+		t.Fatal(err)
+	}
+	if err := q.Enqueue(2); err != nil {
+		t.Fatal(err)
+	}
+	if err := q.Enqueue(3); err != QueueFullErr {
+		t.Fatalf("Enqueue() error = %v, want %v", err, QueueFullErr)
+	}
+
+	head, err := q.Peak()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if head != 1 {
+		t.Fatalf("Peak() = %d, want 1", head)
+	}
+
+	first, err := q.Dequeue()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if first != 1 {
+		t.Fatalf("Dequeue() = %d, want 1", first)
+	}
+
+	second, err := q.Dequeue()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if second != 2 {
+		t.Fatalf("Dequeue() = %d, want 2", second)
+	}
+}
+
+func TestQueue_RawReturnsCopy(t *testing.T) {
+	q := CreateQueue[int](2)
+	if err := q.Enqueue(1); err != nil {
+		t.Fatal(err)
+	}
+
+	raw := q.Raw()
+	raw[0] = 99
+
+	head, err := q.Peak()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if head != 1 {
+		t.Fatalf("Peak() = %d, want 1", head)
+	}
+}

set.go

@@ -62,9 +62,6 @@ func (s Set[T]) Equal(s2 Set[T]) bool {
 	if s.Len() != s2.Len() {
 		return false
 	}
-	if s.Cap() != s2.Cap() {
-		return false
-	}
 	for i := range s {
 		if !reflect.DeepEqual(s[i], s2[i]) {
 			return false

set_test.go

@@ -17,3 +17,15 @@ func TestSet(t *testing.T) {
 		t.Error("s1 and s2 not equal")
 	}
 }
+
+func TestSet_EqualIgnoresCapacity(t *testing.T) {
+	s1 := make(Set[int], 2, 2)
+	s2 := make(Set[int], 2, 4)
+
+	s1[0], s1[1] = 1, 2
+	s2[0], s2[1] = 1, 2
+
+	if !s1.Equal(s2) {
+		t.Error("s1 and s2 not equal")
+	}
+}

slice.go

@@ -56,9 +56,6 @@ func (s Slice[T]) Equal(s2 Slice[T]) bool {
 	if s.Len() != s2.Len() {
 		return false
 	}
-	if s.Cap() != s2.Cap() {
-		return false
-	}
 	for i := range s {
 		if !reflect.DeepEqual(s[i], s2[i]) {
 			return false

slice_test.go

@@ -56,6 +56,18 @@ func TestSlice_Equal(t *testing.T) {
 	}
 }
 
+func TestSlice_EqualIgnoresCapacity(t *testing.T) {
+	a1 := make(Slice[int], 2, 2)
+	a2 := make(Slice[int], 2, 4)
+
+	a1[0], a1[1] = 1, 2
+	a2[0], a2[1] = 1, 2
+
+	if !a1.Equal(a2) {
+		t.Errorf("a1 != a2")
+	}
+}
+
 func TestSlice_Pop(t *testing.T) {
 	a1 := make(Slice[int], 10)
 	a2 := make(Slice[int], 9)
@@ -76,3 +88,17 @@ func TestSlice_Pop(t *testing.T) {
 		t.Errorf("a1 != a2")
 	}
 }
+
+func TestSlice_PopFrontEqual(t *testing.T) {
+	a1 := make(Slice[int], 3, 5)
+	a2 := make(Slice[int], 2, 2)
+
+	a1[0], a1[1], a1[2] = 0, 1, 2
+	a2[0], a2[1] = 1, 2
+
+	a1 = a1.Pop(0)
+
+	if !a1.Equal(a2) {
+		t.Errorf("a1 != a2")
+	}
+}