[REF] mail: clean some JS code

1. Removed `getLocalMessages` method in mailbox, and replaced
   with an override on `getMessages`.

   (This method was used before the distinction was made
   between `getMessages` and `fetchMessages`)

2. Removed unused method `_warnUpdatedUnreadCounter` in
   abstract thread window.

   (Leftover from an early POC)

3. Set the default value `''` for the status of a thread.

   (The method `getStatus` should always return a string)

4. Enforce default value `false` for detached status of channel.

   (The method `isDetached` should always return a boolean)

5. Improve readability of some tests.

   (removed useless variables and/or redundant code)

1 files changed, 1 insertions, 2 deletions

diff --git a/addons/mail/static/src/js/models/threads/channel.js b/addons/mail/static/src/js/models/threads/channel.js
index 8f0f664b6b0..51ebe34a651 100644
--- a/addons/mail/static/src/js/models/threads/channel.js
+++ b/addons/mail/static/src/js/models/threads/channel.js
@@ -51,7 +51,7 @@ var Channel = SearchableThread.extend(ThreadTypingMixin, {
         this._autoswitch = 'autoswitch' in options ? options.autoswitch : true;
         this._commands = undefined;
         this._creatorUID = data.create_uid;
-        this._detached = data.is_minimized;
+        this._detached = data.is_minimized || false;
         this._directPartnerID = undefined;
         this._folded = data.state === 'folded';
         // if set: hide 'Leave channel' button
@@ -66,7 +66,6 @@ var Channel = SearchableThread.extend(ThreadTypingMixin, {
         // number of messages in this channel that are in inbox.
         this._needactionCounter = data.message_needaction_counter || 0;
         this._serverType = data.channel_type;
-        this._status = undefined;
         this._throttleFetchSeen = _.throttle(this._fetchSeen.bind(this), 3000);
         // unique identifier for this channel, which is required for some rpc
         this._uuid = data.uuid;