Guest accounts feature (#11428)

* MM-14139: Creating permissions for invite/promote/demote guests (#10778)

* MM-14139: Creating permissions for invite/promote/demote guests

* Fixing tests

* Adding invite guest api endpoint (#10792)

* Adding invite guest api endpoint

* Adding i18n

* Adding some tests

* WIP

* Migrating Token.Extra info to bigger size (2048)

* Fixing tests

* Adding client function for invite guests

* Adding send guests invites tests

* Renaming file from guest to guest_invite

* Adding Promote/Demote users from/to guest endpoints (#10791)

* Adding Promote/Demote users from/to guest endpoints

* Adding i18n translations

* Adding the client functions

* Using getQueryBuilder function

* Addressing PR review comments

* Adding default channels to users on promte from guest (#10851)

* Adding default channels to users on promte from guest

* Addressing PR review comments

* Fixing merge problems

* Sending websockets events on promote/demote (#11403)

* Sending websockets events on promote/demote

* Fixing merge problems

* Fixing govet shadowing problem

* Fixing feature branch tests

* Avoiding leaking users data through websockets for guest accounts (#11489)

* Avoiding leaking users data through websockets for guest accounts

* Adding tests and fixing code error

* Fixing i18n

* Allow to enable/disable guests and other extra config settings (#11481)

* Allow to enable/disable guests and other extra config settings

* Fixing tests and moving license and config validation to api level

* Update api4/role_test.go

Co-Authored-By: George Goldberg <george@gberg.me>

* Update api4/role_test.go

Co-Authored-By: George Goldberg <george@gberg.me>

* Fixing typo

* fixing tests

* Managing correctly the guest channel leave behavior (#11578)

* MM-15134: Removing guests from teams or system on leave channels if needed

* WIP

* No deactivating the guest user when leave the last team

* Adding a couple of tests

* Fixing shadow variables

* Fixing tests

* fixing tests

* fixing shadow variables

* Adding guest counts for channel stats (#11646)

* Adding guest counts for channel stats

* Adding tests

* Fixing tests

* Fixing guest domain restrictions (#11660)

* Adding needed migration for the database

* Fixing migration

app/channel_test.go

@@ -437,6 +437,63 @@ func TestAddUserToChannelCreatesChannelMemberHistoryRecord(t *testing.T) {
 	assert.NotNil(t, histories[0].LeaveTime)
 }*/
 
+func TestLeaveDefaultChannel(t *testing.T) {
+	th := Setup(t).InitBasic()
+	defer th.TearDown()
+
+	guest := th.CreateGuest()
+	th.LinkUserToTeam(guest, th.BasicTeam)
+
+	townSquare, err := th.App.GetChannelByName("town-square", th.BasicTeam.Id, false)
+	require.Nil(t, err)
+	th.AddUserToChannel(guest, townSquare)
+	th.AddUserToChannel(th.BasicUser, townSquare)
+
+	t.Run("User tries to leave the default channel", func(t *testing.T) {
+		err = th.App.LeaveChannel(townSquare.Id, th.BasicUser.Id)
+		assert.NotNil(t, err, "It should fail to remove a regular user from the default channel")
+		assert.Equal(t, err.Id, "api.channel.remove.default.app_error")
+		_, err = th.App.GetChannelMember(townSquare.Id, th.BasicUser.Id)
+		assert.Nil(t, err)
+	})
+
+	t.Run("Guest leaves the default channel", func(t *testing.T) {
+		err = th.App.LeaveChannel(townSquare.Id, guest.Id)
+		assert.Nil(t, err, "It should allow to remove a guest user from the default channel")
+		_, err = th.App.GetChannelMember(townSquare.Id, guest.Id)
+		assert.NotNil(t, err)
+	})
+}
+
+func TestLeaveLastChannel(t *testing.T) {
+	th := Setup(t).InitBasic()
+	defer th.TearDown()
+
+	guest := th.CreateGuest()
+	th.LinkUserToTeam(guest, th.BasicTeam)
+
+	townSquare, err := th.App.GetChannelByName("town-square", th.BasicTeam.Id, false)
+	require.Nil(t, err)
+	th.AddUserToChannel(guest, townSquare)
+	th.AddUserToChannel(guest, th.BasicChannel)
+
+	t.Run("Guest leaves not last channel", func(t *testing.T) {
+		err = th.App.LeaveChannel(townSquare.Id, guest.Id)
+		require.Nil(t, err)
+		_, err = th.App.GetTeamMember(th.BasicTeam.Id, guest.Id)
+		assert.Nil(t, err, "It should maintain the team membership")
+	})
+
+	t.Run("Guest leaves last channel", func(t *testing.T) {
+		err = th.App.LeaveChannel(th.BasicChannel.Id, guest.Id)
+		assert.Nil(t, err, "It should allow to remove a guest user from the default channel")
+		_, err = th.App.GetChannelMember(th.BasicChannel.Id, guest.Id)
+		assert.NotNil(t, err)
+		_, err = th.App.GetTeamMember(th.BasicTeam.Id, guest.Id)
+		assert.Nil(t, err, "It should remove the team membership")
+	})
+}
+
 func TestAddChannelMemberNoUserRequestor(t *testing.T) {
 	th := Setup(t).InitBasic()
 	defer th.TearDown()