PatternTest.java

package com.hanserwei.patterns.proxy;

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

import java.util.Map;
import java.util.NoSuchElementException;
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 {
  /** 命中缓存省掉读取，显式失效后重新读取. */
  @Test
  void cachesAndInvalidates() {
    MemoryArticleSource source = new MemoryArticleSource(Map.of(1L, "Java"));
    CachingArticleProxy proxy = new CachingArticleProxy(source);
    assertEquals("Java", proxy.find(1));
    assertEquals("Java", proxy.find(1));
    assertEquals(1, source.reads());
    proxy.invalidate(1);
    proxy.find(1);
    assertEquals(2, source.reads());
  }

  /** 读取失败必须保持原异常语义且不缓存失败. */
  @Test
  void preservesMissingArticleFailure() {
    MemoryArticleSource source = new MemoryArticleSource(Map.of());
    ArticleSource proxy = new CachingArticleProxy(source);
    assertThrows(NoSuchElementException.class, () -> proxy.find(99));
    assertThrows(NoSuchElementException.class, () -> proxy.find(99));
    assertEquals(2, source.reads());
  }
}