Programming By Intention/Intro to JUnit

Programming By Intention/Intro to JUnit

Admin

►Astels, p. 50 – “The test in the section titled Programming by Intention…” should read “The test in the section titled Do the Simplest Thing…”

►Quizzes

§Read the question

§Handling quiz opt-outs

§Two items != one item worded two ways

§Refactoring key – Not changing functionality

§Shotgun Surgery = having to make changes in multiple places for one functional change

Programming By Intention

►Methods for keeping code as good as possible

►Guidelines we’ll follow for code we write in this class

Naming

►Nouns for class names/variables (Person, Order, Item)

►Adjectives/generic nouns for interfaces (Testable, Database, Iterator)

►Verbs for method names (Save, calculateTotalInterest)

►getX(), setX(), isX(), hasX()

►Leave out redundant info

Simplicity

►Make code as simple as possible to do what’s needed

►Use refactorings to keep things simple

►Use test-first programming

Assumptions

►Make assumptions while you write your test

►Makes you think about your code from the standpoint of using the code, which means your code plays better with others

►Don’t worry about tracking the assumptions you make, let the compiler tell you

Comments

►Not all comments are bad

►Examples of good comments

§Todo items – incomplete code

§Future refactorings (either by you or someone else)

§Use of uncommon acronym

§Attribution

§Changes made for specific reason (e.g., performance tuning)

§Brief class overview

JUnit

►Developed by Kent Beck and Erich Gamma

►Variant of sUnit (Smalltalk)

►Current version = 3.8.1

►Included in Eclipse and many other IDEs

Structure

►Test Cases

§Extend JUnit TestCase class

§Contain methods which perform actual tests

§Main piece for TDD

►Test Suites

§Contain Test Cases and/or other Test Suites

§Default Test Suite contains all tests

§Generally explicitly defined to allow running subsets of tests

Asserts

►Actual checks performed by test methods

►Two forms – use one with extra string param

►Fail()

►assertTrue/assertFalse

►assertNull/assertNotNull

►assertSame/assertNotSame

►assertEquals