Fix test User check

Author: pengrad

library/src/test/java/com/pengrad/telegrambot/ChatMemberTest.java

@@ -13,7 +13,7 @@ public class ChatMemberTest {
     public static void check(ChatMember chatMember) {
         assertNotNull(chatMember.user());
         assertNotNull(chatMember.status());
-        UserTest.checkUser(chatMember.user());
+        UserTest.checkUser(chatMember.user(), chatMember.status() == ChatMember.Status.creator);
     }
 
 

library/src/test/java/com/pengrad/telegrambot/UserTest.java

@@ -12,10 +12,17 @@
 public class UserTest {
 
     public static void checkUser(User user) {
+        checkUser(user, false);
+    }
+
+    public static void checkUser(User user, boolean full) {
         assertNotNull(user.id());
         assertNotNull(user.firstName());
         assertNotNull(user.username());
-        assertNotNull(user.languageCode());
+        if (full) {
+            assertNotNull(user.lastName());
+            assertNotNull(user.languageCode());
+        }
     }
 
 }