05-JUnit.pdf - Test with JUnit Version 2 April 2013 u00a9...

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Test with JUnit
Version 2 - April 2013
© Maurizio Morisio, Marco Torchiano, 2013
 Test cases can be
 Informal, undocumented
– Also called ‘informal testing’
 Documented
– As text, tables, pseudo code
– As source code (usually in same language as
tested code)

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Testing with JUnit
 JUnit is a testing framework for Java
programs
 Idea of Kent Beck
 It is a framework with unit-testing
functionalities
 Integrated in Eclipse development
Environment

What JUnit does (1)
 JUnit runs a suite of tests and
reports results
 For each test method in the test
suite:
 JUnit calls the method
 If the methods terminates without
problems
– The test is considered passed.

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Example
 Test Stack class
Stack
public class Stack{
public Stack(){ //…
}
public boolean isEmpty(){
}
public int pop(){
}
public void push(int value){
}

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High level test cases
T1 Create stack
Stack empty
Push(10)
Stack not empty
T2 Create stack
Push(10)
Push(-4)
Pop()  -4
Pop()  10
Pop()  empty
Junit test cases
public void testStackT1() {
Stack aStack = new Stack();
assertTrue( “ Stack should be empty! ” ,
aStack.isEmpty());
aStack.push(10);
assertTrue( “ Stack should not be empty! ” ,
!aStack.isEmpty());
}
public void testStackT2() {
Stack aStack = new Stack();
aStack.push(10);
aStack.push(-4);
assertEquals(-4, aStack.pop());
assertEquals(10, aStack.pop());
}

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Junit test cases
public class StackTest extends TestCase {
public void testStackT1() {
Stack aStack = new Stack();
assertTrue( “ Stack should be empty! ” ,
aStack.isEmpty());
aStack.push(10);
assertTrue( “ Stack should not be empty! ” ,
!aStack.isEmpty());
}
public void testStackT2() {
Stack aStack = new Stack();
aStack.push(10);
aStack.push(-4);
assertEquals(-4, aStack.pop());
assertEquals(10, aStack.pop());
}
}
Extends TestCase
Test method name:
test Something
Execution
 Junit executes each test...() method in
the Test class
 If the tests run correctly, nothing is
done
 If a test fails, it throws an
AssertionFailedError
 The JUnit framework catches the error
and deals with it; you don ’ t have to do
anything

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Execution (2)
 setUp() method is run before each
test..() method
 Useful to create the needed clean context
for the test
 tearDown() method is run after
 Useful to clean up, when needed
 They can be override
 protected void runTest() {
setUp() ;
test…();
tearDown() ;
}