1. Smalltalk Testing - SUnit
Programming Languages
HUJI 2010
Yardena Meymann

2. Testing Code needs to be tested
Compilers are capable of checking some trivial errors, this is usually not enough
Several types of tests exist: unit, functional, integration, performance, stress, smoke (a.k.a. sanity), …
In a dynamically typed language, unit testing is integral part of the development

3. What are test for?
Tests are an executable specification of the functionality that they cover, always synchronized with the code
Tests increase the likelihood that the code is correct – finding bugs quickly
TDD – writing tests first, improves interfaces - you see your code from the client’s point of view
The presence of tests gives you the courage to make structural changes to the code: refactoring - essential to prevent creeping entropy

4. Test Driven Development
When creating fresh code, introducing a feature or fixing a bug:
first write tests
see them fail
write code that makes tests succeed
see them pass
re-run tests whenever code is changed (regression)
keep tests passing, fixing code and refactoring tests if needed

5. Properties of Test repeatable run without human intervention
act as a scenario
stable - change frequency lower than the one of the covered functionality
number of tests should be proportional to the number of tested functionalities

6. SUnit Introduction Minimal yet powerful framework
“the mother of unit test frameworks”
developed originally by Kent Beck
SUnit allows to structure tests, describe the context of tests and to run them automatically

7. SUnit Simple test class extends TestCase
setUp method – initialization (fixture)
Methods that start with test
Each method represent a single test
Within methods use assert: condition
or deny:condition
Executing a test: MyTest run: #testMe
Executing all tests: MyTest suite run
Clean up with tearDown method

8. Example Test
'Sample-Test' SampleTest = TestCase ( | emptySet fullSet | 'as yet unclassified' setUp = ( emptySet := Set new. f ullSet := Set with: 5 with: #abc ) testIncludes = ( self assert: (fullSet includes: 5). self assert: (fullSet includes: #abc) testOccurrences = ( self assert: (emptySet occurrencesOf: 0) = 0. self assert: (fullSet occurrencesOf: 5) = 1. fullSet add: 5. self assert: (fullSet occurrencesOf: 5) = 1 testRemove = ( fullSet remove: 5. self assert: (fullSet includes: #abc). self deny: (fullSet includes: 5)

9. Hopscotch Test Runner

10. Hopscotch Test Runner