🆕 #1556 增加微信支付或退款回调的时候返回xml字符串方法

weixin-java-pay/src/test/java/com/github/binarywang/wxpay/bean/notify/WxPayNotifyResponseTest.java

@@ -20,4 +20,22 @@ public class WxPayNotifyResponseTest {
       "<return_msg><![CDATA[OK]]></return_msg>" +
       "</xml>");
   }
+
+  @Test
+  public void testSuccessResp() {
+    final String result = WxPayNotifyResponse.successResp("OK");
+    assertThat(result).isEqualTo("<xml>" +
+      "<return_code><![CDATA[SUCCESS]]></return_code>" +
+      "<return_msg><![CDATA[OK]]></return_msg>" +
+      "</xml>");
+  }
+
+  @Test
+  public void testFailResp() {
+    final String result = WxPayNotifyResponse.failResp("500");
+    assertThat(result).isEqualTo("<xml>" +
+      "<return_code><![CDATA[FAIL]]></return_code>" +
+      "<return_msg><![CDATA[500]]></return_msg>" +
+      "</xml>");
+  }
 }