Extended TreeModel Stubs in order to mock all the methods
Removed Mockery library since it's not used
Added tests when TreeModel::onBeforeDelete returns false
Fixed stub for method mocking
Added tests for TreeModel::forceDelete
Added tests for TreeModel::insertAsFirstChildOf
Added tests for TreeModel::insertAsLastChildOf
Added tests for TreeModel::insertLeftOf
Added tests for TreeModel::insertRightOf
Added tests for TreeModel::moveLeft
Added tests for TreeModel::moveRight
Added tests for TreeModel::moveToLeftOf
Added tests for TreeModel::moveToRightOf
Added tests for TreeModel::makeFirstChildOf
Added tests for TreeModel::makeLastChildOf
Moved data providers methods inside a separate class
Fixed error while loading the whole suite
Added tests for TreeModel::makeRoot
Added tests for TreeModel::getLevel