PatternTest.java

package com.hanserwei.patterns.composite;

import static org.junit.jupiter.api.Assertions.assertEquals;

import java.util.ArrayList;
import java.util.List;
import org.junit.jupiter.api.Test;

/** 验证本模式的协作契约与边界行为. */
public final class PatternTest {
  /** 相同接口支持任意层次的栏目统计. */
  @Test
  void countsNestedStructure() {
    ContentNode root =
        new Section(List.of(new ArticleNode(), new Section(List.of(new ArticleNode()))));
    assertEquals(2, root.articleCount());
    assertEquals(0, new Section(List.of()).articleCount());
  }

  /** 输入列表变化不会改变已经构造好的栏目结构. */
  @Test
  void freezesChildren() {
    List<ContentNode> children = new ArrayList<>();
    children.add(new ArticleNode());
    Section section = new Section(children);
    children.clear();
    assertEquals(1, section.articleCount());
  }
}