1. JUnit Recipes
Zheng-Wen Shen
2007/10/11
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2. References
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3. Brief contents
 Part 1: The Building Blocks
1. Fundamentals
2. Elementary tests
3. Organizing and building JUnit tests
4. Managing test suites
5. Working with test data
6. Running JUnit tests
7. Reporting JUnit results
8. Troubleshooting JUnit
 Part 2: Testing J2EE
 Part 3: More JUnit Techniques
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4. Brief contents
 Part 1: The Building Blocks
1. Fundamentals
2. Elementary tests
3. Organizing and building JUnit tests
4. Managing test suites
5. Working with test data
6. Running JUnit tests
7. Reporting JUnit results
8. Troubleshooting JUnit
 Part 2: Testing J2EE
 Part 3: More JUnit Techniques
4

5. Fundamentals 1/5
 We hate debugging !!
 Code and Fix phases
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6. Fundamentals 2/5
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7. Fundamentals 3/5
 We’d rather be Programmer Testing (Unit
Testing) !!
 Object Testing: testing object in isolation
Application
Manual testing
Obj Obj Obj
Obj Obj Obj
Object testing
Obj Obj Obj Obj
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8. Fundamentals 4/5
 The rhythm of an Object Test
1. Create an object
2. Invoke a method
3. Check the result
Application
Obj Obj Obj
Obj Obj Obj
Object testing
Obj Obj Obj Obj
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9. Fundamentals 5/5
A framework for unit testing
 Tests must be automated
 Tests must verify themselves
 Tests must be easy to run simultaneously
 JUnit (CppUnit, xUnit, etc)
 Writing automated, self-verifying tests in java
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10. Enter JUnit 1/5
The framework of JUnit
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11. Enter JUnit 2/5
A Case Study
public class Money {
private int fAmount;
private String fCurrency;
public Money(int amount, String currency) {
fAmount = amount;
fCurrency = currency;
}
public int amount() {
return fAmount;
}
public String currency() {
return fCurrency;
}
public Money add(Money m) {
return new Money(amount()+m.amount(), currency());
}
}
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12. Enter JUnit 3/5
How to Write A TestCase
public class MoneyTest extends TestCase {
public void testSimpleAdd() {
Money m12CHF= new Money(12, "CHF"); // (1)
Money m14CHF= new Money(14, "CHF");
Money expected= new Money(26, "CHF");
Money result= m12CHF.add(m14CHF); // (2)
assertTrue(expected.equals(result)); // (3)
}
}
(1) Creates the objects we will interact with during the test. This
testing context is commonly referred to as a test's fixture. All we
need for the testSimpleAdd test are some Money objects.
(2) Exercises the objects in the fixture.
(3) Verifies the result
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13. Enter JUnit 4/5
making assertions
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14. Enter JUnit 5/5
Structure of Writing A Test
public class MoneyTest extends TestCase {
private Money f12CHF;
private Money f14CHF;
protected void setUp() {
f12CHF= new Money(12, "CHF");
f14CHF= new Money(14, "CHF");
}
protected void tearDown() {
f12CHF= null;
f14CHF= null;
}
public void testSimpleAdd() {
Money expected= new Money(26, "CHF");
Money result= f12CHF.add(f14CHF);
Assert.assertTrue(expected.equals(result));
}
}
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15. Test-Driven Development (TDD)
 Your system is entirely covered by
tests
 You build your system from loosely
coupled, highly cohesive objects.
 You make steady progress, improving
the system incrementally by making
one test pass, then another, then
another, and so on.
 A passing test is never more than a
few minutes away, giving you
confidence and continual positive
feedback.
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16. Brief contents
 Part 1: The Building Blocks
1. Fundamentals
2. Elementary tests
3. Organizing and building JUnit tests
4. Managing test suites
5. Working with test data
6. Running JUnit tests
7. Reporting JUnit results
8. Troubleshooting JUnit
 Part 2: Testing J2EE
 Part 3: More JUnit Techniques
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17. Elementary tests
1. Test your equals methods
2. Test a method that returns nothing
3. Test a constructor
4. Test a getter
5. Test a setter
6. Test an interface
7. Test throwing the right exception
8. Let collections compare themselves
9. Test a big object for equality
10.Test an object that instantiates other objects
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