PatternTest.java

package com.hanserwei.patterns.builder;

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

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 {
  /** 重用构建器不会改变已创建对象，返回集合也不能修改. */
  @Test
  void buildsIndependentSnapshots() {
    Article.Builder builder = new Article.Builder("Java").addTag("OOP");
    Article first = builder.build();
    builder.addTag("Design");
    assertEquals(List.of("OOP"), first.tags());
    assertEquals(2, builder.build().tags().size());
    assertThrows(UnsupportedOperationException.class, () -> first.tags().add("bad"));
  }

  /** 构建边界拒绝缺失的业务必填值. */
  @Test
  void rejectsBlankTitle() {
    assertThrows(IllegalArgumentException.class, () -> new Article.Builder(" ").build());
  }
}