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:
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
assertTrue
with a boolean.
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.
TestCase test= new MathTest("add") {
public void runTest() {
testAdd();
}
};
test.run();
The dynamic way uses reflection to implement
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.
TestCase= 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
suite
as the entry
point to get a test to run or it will extract the suite automatically.
public static Test suite() {
suite.addTest(new MathTest("testAdd"));
suite.addTest(new MathTest("testDivideByZero"));
return suite;
}
Known Direct Subclasses