fixed testcase

src/test/java/com/alibaba/druid/bvt/proxy/StatisticTest.java

@@ -15,10 +15,13 @@
  */
 package com.alibaba.druid.bvt.proxy;
 
-import junit.framework.Assert;
+import org.junit.Assert;
+
 import junit.framework.TestCase;
 
+import com.alibaba.druid.proxy.DruidDriver;
 import com.alibaba.druid.stat.JdbcConnectionStat;
+import com.alibaba.druid.stat.JdbcStatManager;
 
 public class StatisticTest extends TestCase {
 
@@ -30,4 +33,9 @@ public class StatisticTest extends TestCase {
         stat.setActiveCount(2);
         Assert.assertEquals(2, stat.getActiveMax());
     }
+    
+    protected void tearDown() throws Exception {
+        DruidDriver.getProxyDataSources().clear();
+        Assert.assertEquals(0, JdbcStatManager.getInstance().getSqlList().size());
+    }
 }