Java Hierarchy Fluent Builder

Tree.java

package org.foo;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.stream.Collectors;
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.Test;

public class Node {
	private static final String ROOT = "ROOT";
	String name;
	String alias;
	List<Node> children;

	public Node(Builder builder) {
		this.name = builder.name;
		this.alias = builder.alias;
		this.children = builder.children.stream().map(Builder::build).collect(Collectors.toList());
	}

	public static Builder builder() {
		return new Builder();
	}
	public static Builder builder(String name) {
		return new Builder(name);
	}

	public static class Builder {
		String name;
		String alias;
		List<Builder> children;

		public Builder() {
			this.name = ROOT;
			this.children = new ArrayList<>();
		}

		public Builder(String name) {
			this.name = name;
			this.children = new ArrayList<>();
		}

		public Builder withChild(Builder child) {
			this.children.add(child);
			return this;
		}

		public Builder withChildren(List<Builder> builders) {
			 builders.forEach(this::withChild);
			 return this;
		}

		public Node build() {
			return new Node(this);
		}
	}
//
//	@Test
//	void testTrivial() {
//		Node tree = Node.builder()
//				.withChild(Node.builder("name"))
//				.build();
//		// 1st layer
//		assertEquals(1, tree.children.size());
//		assertEquals("name", tree.children.get(0).name);
//
//	}
//
//	@Test
//	void test2Child() {
//		Node tree = Node.builder()
//				.withChild(Node.builder("one"))
//				.withChild(Node.builder("two"))
//				.build();
//		// 1st layer
//		assertEquals(2, tree.children.size());
//		assertEquals("one", tree.children.get(0).name);
//		assertEquals("two", tree.children.get(1).name);
//		// 2nd layer
//		assertEquals(0, tree.children.get(0).children.size());
//		assertEquals(0, tree.children.get(1).children.size());
//
//	}
//
//
//	@Test
//	void test2Deep() {
//		Node tree = Node.builder()
//				.withChild(Node.builder("one")
//						.withChild(Node.builder("one.one"))
//						.withChild(Node.builder("one.two"))
//				)
//				.withChild(Node.builder("two"))
//				.build();
//		// 1st layer
//		assertEquals(2, tree.children.size());
//		assertEquals("one", tree.children.get(0).name);
//		assertEquals("two", tree.children.get(1).name);
//		// 2nd layer
//		assertEquals(2, tree.children.get(0).children.size());
//		assertEquals("one.one", tree.children.get(0).children.get(0).name);
//		assertEquals("one.two", tree.children.get(0).children.get(1).name);
//		assertEquals(0, tree.children.get(1).children.size());
//		// 3rd layer
//		assertEquals(0, tree.children.get(0).children.get(0).children.size());
//		assertEquals(0, tree.children.get(0).children.get(1).children.size());
//	}
//
//	@Test
//	void test3Deep() {
//		Node tree = Node.builder()
//				.withChild(Node.builder("one")
//						.withChild(Node.builder("one.one"))
//						.withChild(Node.builder("one.two")
//								.withChild(Node.builder("one.two.one")))
//				)
//				.withChild(Node.builder("two"))
//				.build();
//		// 1st layer
//		assertEquals(2, tree.children.size());
//		assertEquals("one", tree.children.get(0).name);
//		assertEquals("two", tree.children.get(1).name);
//		// 2nd layer
//		assertEquals(2, tree.children.get(0).children.size());
//		assertEquals("one.one", tree.children.get(0).children.get(0).name);
//		assertEquals("one.two", tree.children.get(0).children.get(1).name);
//		assertEquals(0, tree.children.get(1).children.size());
//		// 3rd layer
//		assertEquals(0, tree.children.get(0).children.get(0).children.size());
//		assertEquals(1, tree.children.get(0).children.get(1).children.size());
//		assertEquals("one.two.one", tree.children.get(0).children.get(1).children.get(0).name);
//		// 4th layer
//		assertEquals(0, tree.children.get(0).children.get(1).children.get(0).children.size());
//	}
}