Becatrue/88/init test

[BECATRUE]

This PR will close #88.

• Organize testing system.
• Implement the first testing for swift.app.

You can test as below:

pip install coverage                        // only first time

python -m coverage run -m tests.test_swift  // run test
python -m coverage report                   // show report

[kangz12345]

Please link an issue or use the closing keyword :)

[BECATRUE]

Please link an issue or use the closing keyword :)

I forgot it again😂

[BECATRUE]

I removed the redundant blank line!