fixed testcase

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

@@ -28,8 +28,12 @@ import java.sql.Statement;
 import java.sql.Types;
 import java.util.Calendar;
 
+import org.junit.Assert;
+
 import junit.framework.TestCase;
 
+import com.alibaba.druid.proxy.DruidDriver;
+import com.alibaba.druid.stat.JdbcStatManager;
 import com.alibaba.druid.util.JdbcUtils;
 
 public class PreparedStatementTest extends TestCase {
@@ -64,6 +68,9 @@ public class PreparedStatementTest extends TestCase {
 
     protected void tearDown() throws Exception {
         dropTable();
+        
+        DruidDriver.getProxyDataSources().clear();
+        Assert.assertEquals(0, JdbcStatManager.getInstance().getSqlList().size());
     }
 
     @SuppressWarnings("deprecation")