Wrote some tests for binding the configurations.
Add test case for playing mp3 file in child process.
Add test case for playing sound.
Fix a test case to pass.
Add a test case for run(). Now status is RED.
Fix a bug that raises a error when @argv is different from @ARGV

related #4
Improve a test case for run(). (It has already GREEN).
Improve a test case for _play_sound (It has already GREEN)

Use mock object
Fix a wrong description in a test.
Improve test case No.04

This commit is associated with #4
Fix structure of test code.
Add description about number of tests.
Remove unnecessary BEGIN clause.
Merge branch 'feature/write_some_tests' of github.com:moznion/App--WithSound into feature/write_some_tests