Unit Tests, what are they? Styles and good practices.

1. Unit testing Vocabulary, styles, toys ____________________________

3. ____________________________ Vocabulary “ Unit tests are tests written with JUnit” (naive, simplistic, false ) Unit Tests Integration, Functional, Acceptance Tests -> also written with JUnit If Unit tests cannot be defined via it’s Unit Testing Framework, what are they? Unit Testing : - tests that perform a verification of a unit of code (article) - “a unit test has no dependencies” (article) - a method of testing that verifies individual units of source code are working properly (wikipedia) Integration testing : - the part of software testing in which individual software modules are combined and tested together as a group.

4. ____________________________ Vocabulary Unit Tests & not just tests “ One of the challenges of unit testing is to sufficiently decouple the multiple units of code that make up an application so that each unit can be tested individually.” Unit Tests -> tend to become mini-integration tests! Why should I Care? Testing simple functionality (ex: new methods) in Integration Tests can lead to: Fragile Tests Unrepeatable Tests … Maintenance Nightmare 

6. ____________________________ Styles What: Order : must fill itself from Warehouse If Warehouse contains the product quantity requested by Order: - Order becomes filled, Warehouse quantity adjusted. If Warehouse does not contain necessary quantity: -Order does not become filled. Warehouse unchanged. Example

7. ____________________________ Styles Regular test

8. ____________________________ Styles How do we test a mail was sent?! Stubs With a Stub :

9. “ Once,” said the Mock Turtle at last, with a deep sigh, “I was a real Turtle.” (Alice In Wonderland, Lewis Carroll) ____________________________ Styles Mocks

10. ____________________________ Styles Mock test: jMock

11. ____________________________ Styles We’re late!

15. ____________________________ Vocabulary Good Unit Tests “ Uncle Bob” suggests the F.I.R.S.T acronym in “Clean Code” to describe what well written (clean) unit tests should look like : F ast - they should run quickly. This encourages you to run them often. (framework) I ndependent - they should not depend on each other. It should be possible to run the tests in any order. R epeatable - it should be possible to run them in any environment. They should be environment independent. S elf-Validating - they should either pass or fail. (framework) T imely - they should be written in a timely manner i.e. just before the production code is written.

16. ____________________________ Toys Mockito

17. questions? ____________________________ http :// martinfowler.com/articles/mocksArentStubs.html http://code.google.com/p/mockito/ http://xunitpatterns.com/Mocks,%20Fakes,%20Stubs%20and%20Dummies.html Martin Fowler: “ Refactoring . Improving the design of existing code ” http://blogs.thoughtworks.com/ Robert “Uncle Bob” Martin: “ Clean Code : A Handbook of Agile Software Craftsmanship” http://mockobjects.com/ http://benpryor.com/blog/2007/01/16/state-based-vs-interaction-based-unit-testing/