diff --git a/t_iter-list_test.go b/t_iter-list_test.go
new file mode 100644
index 0000000..d7a78b3
--- /dev/null
+++ b/t_iter-list_test.go
@@ -0,0 +1,162 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// t_iter-list_test.go
+package expr
+
+import (
+	"io"
+	"testing"
+)
+
+func TestNewListIterator(t *testing.T) {
+	list := newListA("a", "b", "c", "d")
+	it := NewListIterator(list, []any{1, 3, 1})
+	if item, err := it.Next(); err != nil {
+		t.Errorf("error: %v", err)
+	} else if item != "b" {
+		t.Errorf("expcted %q, got %q", "b", item)
+	} else {
+		t.Logf("Next: %v", item)
+	}
+}
+
+func TestNewListIterator2(t *testing.T) {
+	list := newListA("a", "b", "c", "d")
+	it := NewListIterator(list, []any{3, 1, -1})
+	if item, err := it.Next(); err != nil {
+		t.Errorf("error: %v", err)
+	} else if item != "d" {
+		t.Errorf("expcted %q, got %q", "d", item)
+	} else {
+		t.Logf("Next: %v", item)
+	}
+}
+
+func TestNewListIterator3(t *testing.T) {
+	list := newListA("a", "b", "c", "d")
+	it := NewListIterator(list, []any{1, -1, 1})
+	if item, err := it.Next(); err != nil {
+		t.Errorf("error: %v", err)
+	} else if item != "b" {
+		t.Errorf("expcted %q, got %q", "b", item)
+	} else {
+		t.Logf("Next: %v", item)
+	}
+}
+
+func TestNewIterList2(t *testing.T) {
+	list := []any{"a", "b", "c", "d"}
+	it := NewArrayIterator(list)
+	if item, err := it.Next(); err != nil {
+		t.Errorf("error: %v", err)
+	} else if item != "a" {
+		t.Errorf("expcted %q, got %q", "a", item)
+	} else {
+		t.Logf("Next: %v", item)
+	}
+}
+
+func TestNewIterList3(t *testing.T) {
+	list := []any{"a", "b", "c", "d"}
+	it := NewAnyIterator(list)
+	if item, err := it.Next(); err != nil {
+		t.Errorf("error: %v", err)
+	} else if item != "a" {
+		t.Errorf("expcted %q, got %q", "a", item)
+	} else {
+		t.Logf("Next: %v", item)
+	}
+}
+
+func TestNewIterList4(t *testing.T) {
+	list := any(nil)
+	it := NewAnyIterator(list)
+	if _, err := it.Next(); err != io.EOF {
+		t.Errorf("error: %v", err)
+	}
+}
+
+func TestNewIterList5(t *testing.T) {
+	list := "123"
+	it := NewAnyIterator(list)
+	if item, err := it.Next(); err != nil {
+		t.Errorf("error: %v", err)
+	} else if item != "123" {
+		t.Errorf("expcted %q, got %q", "123", item)
+	} else {
+		t.Logf("Next: %v", item)
+	}
+}
+
+func TestNewIterList6(t *testing.T) {
+	list := newListA("a", "b", "c", "d")
+	it1 := NewAnyIterator(list)
+	it := NewAnyIterator(it1)
+	if item, err := it.Next(); err != nil {
+		t.Errorf("error: %v", err)
+	} else if item != "a" {
+		t.Errorf("expcted %q, got %q", "a", item)
+	} else {
+		t.Logf("Next: %v", item)
+	}
+}
+func TestNewString(t *testing.T) {
+	list := "123"
+	it := NewAnyIterator(list)
+	if s := it.String(); s != "$(#1)" {
+		t.Errorf("expected $(#1), got %s", s)
+	}
+}
+
+func TestHasOperation(t *testing.T) {
+
+	list := newListA("a", "b", "c", "d")
+	it := NewListIterator(list, []any{1, 3, 1})
+	hasOp := it.HasOperation("reset")
+	if !hasOp {
+		t.Errorf("HasOperation(reset) must be true, got false")
+	}
+}
+
+func TestCallOperationReset(t *testing.T) {
+
+	list := newListA("a", "b", "c", "d")
+	it := NewListIterator(list, []any{1, 3, 1})
+	if v, err := it.CallOperation("reset", nil); err != nil {
+		t.Errorf("Error on CallOperation(reset): %v", err)
+	} else {
+		t.Logf("Reset result: %v", v)
+	}
+}
+
+func TestCallOperationIndex(t *testing.T) {
+
+	list := newListA("a", "b", "c", "d")
+	it := NewListIterator(list, []any{1, 3, 1})
+	if v, err := it.CallOperation("index", nil); err != nil {
+		t.Errorf("Error on CallOperation(index): %v", err)
+	} else {
+		t.Logf("Index result: %v", v)
+	}
+}
+
+func TestCallOperationCount(t *testing.T) {
+
+	list := newListA("a", "b", "c", "d")
+	it := NewListIterator(list, []any{1, 3, 1})
+	if v, err := it.CallOperation("count", nil); err != nil {
+		t.Errorf("Error on CallOperation(count): %v", err)
+	} else {
+		t.Logf("Count result: %v", v)
+	}
+}
+
+func TestCallOperationUnknown(t *testing.T) {
+
+	list := newListA("a", "b", "c", "d")
+	it := NewListIterator(list, []any{1, 3, 1})
+	if v, err := it.CallOperation("unknown", nil); err == nil {
+		t.Errorf("Expected error on CallOperation(unknown), got %v", v)
+	}
+}