add test for creating map when zero size is provided

e2e_test.go

@@ -19,6 +19,14 @@ func TestMapCreation(t *testing.T) {
 	if m.Len() != 0 {
 		t.Errorf("new map should be empty but has %d items.", m.Len())
 	}
+
+	t.Run("default size is used when zero is provided", func(t *testing.T) {
+		m := New[int, int](0)
+		index := m.metadata.Load().index
+		if len(index) != defaultSize {
+			t.Error("map index size is not as expected")
+		}
+	})
 }
 
 func TestOverwrite(t *testing.T) {

map.go

@@ -64,7 +64,7 @@ type (
 func New[K hashable, V any](size ...uintptr) *Map[K, V] {
 	m := &Map[K, V]{listHead: newListHead[K, V]()}
 	m.numItems.Store(0)
-	if len(size) > 0 && size[0] > 0 {
+	if len(size) > 0 && size[0] != 0 {
 		m.allocate(size[0])
 	} else {
 		m.allocate(defaultSize)