PatternTest.java

package com.hanserwei.patterns.singleton;

import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertSame;
import static org.junit.jupiter.api.Assertions.assertTrue;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
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 {
  /** 不同任务访问同一策略实例. */
  @Test
  void sharesIdentityAcrossThreads() throws Exception {
    try (ExecutorService executor = Executors.newVirtualThreadPerTaskExecutor()) {
      Future<SitePolicy> first = executor.submit(() -> SitePolicy.INSTANCE);
      Future<SitePolicy> second = executor.submit(() -> SitePolicy.INSTANCE);
      assertSame(first.get(), second.get());
    }
  }

  /** 长度上限包括边界，空白标题被拒绝. */
  @Test
  void validatesTitleBoundary() {
    assertTrue(SitePolicy.INSTANCE.accepts("a".repeat(80)));
    assertFalse(SitePolicy.INSTANCE.accepts("a".repeat(81)));
    assertFalse(SitePolicy.INSTANCE.accepts(" "));
  }
}