add test for reverseOdrer method

weixin-java-pay/src/main/java/com/github/binarywang/wxpay/config/WxPayConfig.java

@@ -135,7 +135,7 @@ public class WxPayConfig {
 
   public SSLContext initSSLContext() {
     if (null == mchId) {
-      throw new IllegalArgumentException("请確保mchId已設置");
+      throw new IllegalArgumentException("请确保商户号mch_id已设置");
     }
 
     File file = new File(this.keyPath);

weixin-java-pay/src/test/java/com/github/binarywang/wxpay/service/impl/WxPayServiceImplTest.java

@@ -210,4 +210,23 @@ public class WxPayServiceImplTest {
       .build());
     this.logger.info(result.toString());
   }
+
+  @Test
+  public void testGetConfig() throws Exception {
+  }
+
+  @Test
+  public void testSetConfig() throws Exception {
+  }
+
+  @Test
+  public void testReverseOrder() throws Exception {
+    WxPayOrderReverseResult result = this.payService.reverseOrder(WxPayOrderReverseRequest.newBuilder()
+      .outTradeNo("1111")
+      .build());
+    assertNotNull(result);
+    this.logger.info(result.toString());
+
+  }
+
 }