juit 用assertThat 提示我找不到符号

Question

代码如下，用的是intelij idea社区版。import org.junit.Test;import static org.junit.Assert.assertThat;import static sun.nio.cs.Surrogate.is;public class PlayerTest {  public void should_return_3_when_status_is_3(){        Player player = new Player();        assertThat(player.getStatus(),is(3));    }}提示错误`找不到符号符号： 方法 assertThat(int,boolean)位置： 类 PlayerTest`项目的IML文件如下<?xml version="1.0" encoding="UTF-8"?><module type="JAVA_MODULE" version="4">  <component name="NewModuleRootManager" inherit-compiler-output="true">    <exclude-output />    <content url="file://$MODULE_DIR$">      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />      <sourceFolder url="file://$MODULE_DIR$/test" isTestSource="true" />    </content>    <orderEntry type="inheritedJdk" />    <orderEntry type="sourceFolder" forTests="false" />    <orderEntry type="module-library" scope="TEST">      <library>        <CLASSES>          <root url="jar://$APPLICATION_HOME_DIR$/lib/junit-4.10.jar!/" />        </CLASSES>        <JAVADOC />        <SOURCES />      </library>    </orderEntry>  </component></module>