add lock fair testcase

src/test/java/com/alibaba/druid/bvt/pool/LockFairTest.java

@@ -0,0 +1,29 @@
+package com.alibaba.druid.bvt.pool;
+
+import java.util.concurrent.locks.ReentrantLock;
+
+import junit.framework.Assert;
+import junit.framework.TestCase;
+
+import com.alibaba.druid.pool.DruidDataSource;
+import com.alibaba.druid.util.JdbcUtils;
+
+public class LockFairTest extends TestCase {
+
+    private DruidDataSource dataSource;
+    
+    protected void setUp() throws Exception {
+        dataSource = new DruidDataSource();
+    }
+    
+    protected void tearDown() throws Exception {
+        JdbcUtils.close(dataSource);
+    }
+
+    public void test_fair() throws Exception {
+        Assert.assertEquals(false, ((ReentrantLock)dataSource.getLock()).isFair());
+        dataSource.setMaxWait(100);
+        
+        Assert.assertEquals(true, ((ReentrantLock)dataSource.getLock()).isFair());
+    }
+}