Design – Build – Run: Applied Practices and Principles for Production-Ready Software Development

23.4. Summary

Testing is vitally important and you need to consider all the different types of tests that you are going to carry out. You need to model the application components to determine the unit tests, integration tests, and smoke tests. Using interfaces and factories from the outset enables you to make (and change) decisions as the project progresses without unduly impacting construction. Stubs and simulators can provide real value when developed and used appropriately.

The following are the key points to take away from this chapter:

• Determine the types of developer tests to carry out. The tests should be categorized into the following areas:

  • Unit tests should cover complete components or classes, including exception scenarios.

  • Integration tests should cover multiple interactions between components as well as exception scenarios.

  • Smoke tests should cover the core functionality of the application.

• The value of unit and integration tests can decrease as the project progresses. The following should be considered when devising unit and integration tests:

  • Maintaining redundant tests and test matter is a waste of time and money.

  • Test the application, not the tests.

• Have the right tools and processes in place. To support thorough testing you need to have all the right tools and processes in place, including:

  • Test execution tools.

  • Expected and actual results comparison tools.

• Use the Factory Pattern. The software factory pattern that can be used to plug in different components.

  • Interfaces ...