修复toMap方法的bug，并加入单元测试代码

weixin-java-mp/src/test/java/me/chanjar/weixin/mp/bean/pay/result/WxPayBaseResultTest.java

@@ -0,0 +1,49 @@
+package me.chanjar.weixin.mp.bean.pay.result;
+
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+import java.util.Map;
+
+/**
+ * <pre>
+ * Created by Binary Wang on 2017-01-04.
+ * @author <a href="https://github.com/binarywang">binarywang(Binary Wang)</a>
+ * </pre>
+ */
+public class WxPayBaseResultTest {
+  @Test
+  public void testToMap() throws Exception {
+    WxPayOrderQueryResult result = new WxPayOrderQueryResult();
+    result.setXmlString("<xml>\n" +
+      "   <return_code><![CDATA[SUCCESS]]></return_code>\n" +
+      "   <return_msg><![CDATA[OK]]></return_msg>\n" +
+      "   <appid><![CDATA[wx2421b1c4370ec43b]]></appid>\n" +
+      "   <mch_id><![CDATA[10000100]]></mch_id>\n" +
+      "   <device_info><![CDATA[1000]]></device_info>\n" +
+      "   <nonce_str><![CDATA[TN55wO9Pba5yENl8]]></nonce_str>\n" +
+      "   <sign><![CDATA[BDF0099C15FF7BC6B1585FBB110AB635]]></sign>\n" +
+      "   <result_code><![CDATA[SUCCESS]]></result_code>\n" +
+      "   <openid><![CDATA[oUpF8uN95-Ptaags6E_roPHg7AG0]]></openid>\n" +
+      "   <is_subscribe><![CDATA[Y]]></is_subscribe>\n" +
+      "   <trade_type><![CDATA[MICROPAY]]></trade_type>\n" +
+      "   <bank_type><![CDATA[CCB_DEBIT]]></bank_type>\n" +
+      "   <total_fee>1</total_fee>\n" +
+      "   <fee_type><![CDATA[CNY]]></fee_type>\n" +
+      "   <transaction_id><![CDATA[1008450740201411110005820873]]></transaction_id>\n" +
+      "   <out_trade_no><![CDATA[1415757673]]></out_trade_no>\n" +
+      "   <attach><![CDATA[订单额外描述]]></attach>\n" +
+      "   <time_end><![CDATA[20141111170043]]></time_end>\n" +
+      "   <trade_state><![CDATA[SUCCESS]]></trade_state>\n" +
+      "</xml>");
+    Map<String, String> map = result.toMap();
+    System.out.println(map);
+
+    Assert.assertEquals("SUCCESS", map.get("return_code"));
+    Assert.assertEquals("订单额外描述", map.get("attach"));
+
+    result.setXmlString("");
+    System.out.println(result.toMap());
+  }
+
+}