Java™ Application Development on Linux - Dator

306Chapter 13JUnit: Automating Unit TestingtestCreateSub() is a single JUnit test which asserts various conditions aboutvarious invocations of the createSub() method. Note that all of the assertionsencountered in the execution of the test class must pass for the test to pass.So what happens if an assertion fails? The assert method will throw an exception,reporting the failure. In JUnit terminology, a failure is a test that didn’tpass, whereas an error is a problem with the running of the test. A missing classor a null pointer exception are errors, whereas an assertNotNull() call failingis considered a test failure.The handy thing about the exceptions that the assert methods throw isthat they are, technically speaking, not java.lang.Exception throwables butrather belong to the java.lang.Error type of throwable. (Don’t confuse thistechnical Java use of the word “error” with our more informal use in the previousdiscussion of failure versus error.) To quote from the Javadoc page forjava.lang.Error:A method is not required to declare in its throws clause any subclasses ofError that might be thrown during the execution of the method but notcaught, since these errors are abnormal conditions that should never occur.So the use of Error by JUnit’s various assert methods is done simply as aconvenience for us test developers, so that we don’t have to put throws ...clauses on all of our method declarations.13.5.1 JUnit AssertionsThese are the various test assertions available with JUnit:• assertEquals(), comparing• boolean with boolean• char with char• short with short• int with int• long with long• float with float• double with double• Object with Object• String with String