Creating Unit Tests

Any method in a Java class can be a test method, as long as it is tagged with the @TestMethod annotation. Within the test method, use assert statements like this one to compare expected results to actual results: RunTest.assertEquals(expected, actual).

Here's a template for a test method:

<syntaxhighlight lang="java" enclose="div">

/**

* javadoc comment
*/

@TestMethod public void testSomeBehavior() throws Exception {

   String expect = "It's working!";         
   String actual = someBehavior();          // Invoke the method you're testing

   RunTest.assertEquals(expect, actual);

} </syntaxhighlight>

Tip: Give your test methods meaningful names that tell what the test was trying to do. That way, when you're reading a report that identifies a failure, the name will tell you a lot. For example: testTwoPlusTwoEqualsFour.

Considerations

• A single test method can contain multiple assertions.
• Each successful assertion adds to the success count and the count of total tests.
• A test method may contain no assertions at all. In that case, it runs to completion, but the test is not counted as a success.
• A test may fail either because an exception occurs, or because an assertion fails.
• In either case, the message is recorded. (For an exception, a stack trace is also recorded.)
• Whether an assertion succeeds or fails, the method continues running. It is only interrupted by an exception.
• If multiple assertions fail, all of the failure messages are reported.
• If one or more assertions fail, and then an exception occurs, all of the messages are reported, along with the exception.
• The test method (testSomeBehavior, above) must be public. If it isn't, an IllegalAccessException occurs when the @TestMethod annotation causes the Unit Test Framework to attempt execution.