* add initial python sample
* add all of ios and android tests
* apply formatter
* add >=0.28 to avoid version error
* tweak versions of default OS
* convert some tests to unittest based ones
* use single quote mainly
* use {} format style for string
* use format syntax
* apply format and tweak assertions
* use is None
* use assert raise
* speficy a number of elements
* tweak exception
* move app path to helper
* tweak assertion conditions
* remove .close since with open() close file automatically
