junit

http://junit.sourceforge.net/junit3.8.1/javadoc/junit/framework/TestCase.html

1
2
3
4
5
6
7

java.lang.Object
  |
  +--junit.framework.Assert
        |
        +--junit.framework.TestCase

• public abstract class TestCase
• extends Assert
• implements Test

A test case defines the fixture to run multiple tests. To define a test case
1) implement a subclass of TestCase
2) define instance variables that store the state of the fixture
3) initialize the fixture state by overriding setUp
4) clean-up after a test by overriding tearDown.
Each test runs in its own fixture so there can be no side effects among test runs. Here is an example:

1
2
3
4
5
6
7
8
9

public class MathTest extends TestCase {
    protected double fValue1;
    protected double fValue2;

   protected void setUp() {
        fValue1= 2.0;
        fValue2= 3.0;
    }
}

For each test implement a method which interacts with the fixture. Verify the expected results with assertions specified by calling

1

assertTrue

with a boolean.

1
2
3
4

public void testAdd() {
    double result= fValue1 + fValue2;
    assertTrue(result == 5.0);
}

Once the methods are defined you can run them. The framework supports both a static type safe and more dynamic way to run a test. In the static way you override the runTest method and define the method to be invoked. A convenient way to do so is with an anonymous inner class.

1
2
3
4
5
6

TestCase test= new MathTest("add") {
       public void runTest() {
           testAdd();
       }
};
test.run();

The dynamic way uses reflection to implement

1

runTest

. It dynamically finds and invokes a method. In this case the name of the test case has to correspond to the test method to be run.

1
2

TestCase test = new MathTest("testAdd");
test.run();

The tests to be run can be collected into a TestSuite. JUnit provides different

test runners

which can run a test suite and collect the results. A test runner either expects a static method

1

suite

as the entry point to get a test to run or it will extract the suite automatically.

1
2
3
4
5

public static Test suite() {
     suite.addTest(new MathTest("testAdd"));
     suite.addTest(new MathTest("testDivideByZero"));
     return suite;
 }