fix bug

hutool-cache/src/test/java/cn/hutool/cache/WeakCacheTest.java

@@ -0,0 +1,21 @@
+package cn.hutool.cache;
+
+import cn.hutool.cache.impl.WeakCache;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class WeakCacheTest {
+
+	@Test
+	public void removeTest(){
+		final WeakCache<String, String> cache = new WeakCache<>(-1);
+		cache.put("abc", "123");
+		cache.put("def", "456");
+
+		Assert.assertEquals(2, cache.size());
+
+		cache.remove("abc");
+
+		Assert.assertEquals(1, cache.size());
+	}
+}