Too Long; Didn't Read
For the purpose of this post, we will call as "<a href="https://hackernoon.com/tagged/production-code" target="_blank"><strong>Production Code</strong></a><strong>"</strong> the part of the system that contains the logic of the project and is run in production. We will call as "<a href="https://hackernoon.com/tagged/test-code" target="_blank"><strong>Test Code</strong></a><strong>"</strong> the part of the project that contains the tests which verify if the application (Production Code) work as expected.