diff --git a/dom/mobilemessage/tests/marionette/test_getthreads.js b/dom/mobilemessage/tests/marionette/test_getthreads.js
index 75b363a57a5..8a791d9d1a3 100644
--- a/dom/mobilemessage/tests/marionette/test_getthreads.js
+++ b/dom/mobilemessage/tests/marionette/test_getthreads.js
@@ -338,35 +338,37 @@ checkFuncs.push(checkThread.bind(null, ["thread 14-1", "thread 14-2",
                                         "thread 14-3"],
                                  "thread 14-3", 0, ["5555211014"]));
 
-//[Thread 15]
-//Three sent message, unreadCount = 0;
-//One participant but might be merged to 555211015, participants = ["5555211015"].
+// [Thread 15]
+// One sent message, unreadCount = 0;
+// One participant but might be merged to 555211015, participants = ["5555211015"].
 tasks.push(sendMessage.bind(null, "5555211015", "thread 15-1"));
 checkFuncs.push(checkThread.bind(null, ["thread 15-1"],
                                  "thread 15-1", 0, ["5555211015"]));
 
-//[Thread 16]
-//Three sent message, unreadCount = 0;
-//One participant but might be merged to 5555211015, participants = ["555211015"].
+// [Thread 16]
+// One sent message, unreadCount = 0;
+// One participant but might be merged to 5555211015, participants = ["555211015"].
 tasks.push(sendMessage.bind(null, "555211015", "thread 16-1"));
 checkFuncs.push(checkThread.bind(null, ["thread 16-1"],
                                  "thread 16-1", 0, ["555211015"]));
 
-//[Thread 17]
-//Three sent message, unreadCount = 0;
-//One participant with two aliased addresses, participants = ["555211017"].
-tasks.push(sendMessage.bind(null, "+5511555211017", "thread 17-1"));
-tasks.push(sendMessage.bind(null, "555211017",      "thread 17-2"));
+// [Thread 17]
+// Brazil number format: +55-aa-nnnnnnnn. (2-digit area code and 8-digit number)
+// Two sent messages, unreadCount = 0;
+// One participant with two aliased addresses, participants = ["+551155211017"].
+tasks.push(sendMessage.bind(null, "+551155211017", "thread 17-1"));
+tasks.push(sendMessage.bind(null, "1155211017",      "thread 17-2"));
 checkFuncs.push(checkThread.bind(null, ["thread 17-1", "thread 17-2"],
-                                 "thread 17-2", 0, ["+5511555211017"]));
+                                 "thread 17-2", 0, ["+551155211017"]));
 
-//[Thread 18]
-//Three sent message, unreadCount = 0;
-//One participant with two aliased addresses, participants = ["555211018"].
-tasks.push(sendMessage.bind(null, "555211018",      "thread 18-1"));
-tasks.push(sendMessage.bind(null, "+5511555211018", "thread 18-2"));
+// [Thread 18]
+// Brazil number format: +55-aa-nnnnnnnn. (2-digit area code and 8-digit number)
+// Two sent messages, unreadCount = 0;
+// One participant with two aliased addresses, participants = ["1155211018"].
+tasks.push(sendMessage.bind(null, "1155211018",      "thread 18-1"));
+tasks.push(sendMessage.bind(null, "+551155211018", "thread 18-2"));
 checkFuncs.push(checkThread.bind(null, ["thread 18-1", "thread 18-2"],
-                                 "thread 18-2", 0, ["555211018"]));
+                                 "thread 18-2", 0, ["1155211018"]));
 
 // Check threads.
 tasks.push(getAllThreads.bind(null, function(threads) {