Why Great testing includes isolation Most parts of a software system do not work in isolation, but collaborate with other parts to get their job done. In a lot of cases, we do not care about using real collaborators implementation in unit testing, as we trust these collaborators. Mock Objects replace collaborators of the unit under test. How Isolation involves Mock Objects To test a unit in isolation or mount a sufficient environment, we have to simulate the collaborators in the test.
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Tells JUnit a collection of classes to run. Used with the RunWith Suite. Test Class optional Timeout optional Used to indicate a test method. The class parameter is used to indicate an exception is expected to be thrown and what the exception is. The timeout parameter specifies in milliseconds how long to allow a single test to run.
If the test takes longer than the timeout, it will be considered a failure. Table 3. Annotations Figure 3 shows two test cases, one using JUnit 3. Figure 3 JUnit 3. Any plain old java object POJO can be run as a test with the appropriate annotations. Test Suites A test suite is a collection of tests cases. It is used to run a collection of tests and aggregate the results.
In JUnit 3. There are two ways to create a test suite, programmatically and with annotations. For example, if the method bar is to be tested on the object foo, the test should create a new instance of foo for each test. This will prevent any state related issues from interfering with future tests variables left initialized from previous tests, objects left with invalid data, etc. Figure 1 is an example of a fixture. It creates a new instance of foo for each test and closes it after the execution of each test.
This prevents any carryover issues from affecting the current test. Section 8 Mock Objects Unit testing is the testing of a component in isolation. However,in most systems objects have many dependencies. In order to be able to test code in isolation, those dependencies need to be removed to prevent any impact on test code by the dependant code. To create this isolation, mock objects are used to replace the real objects.
Section 9 EasyMock EasyMock is a framework for creating mock objects using the java. Proxy object. When a mock object is created, a proxy object takes the place of the real object. The proxy object gets its definition from the interface or class you pass when creating the mock.
EasyMock has two sets of APIs. One is intended for creation and manipulation of mock objects that are based on interfaces, the other on classes org. EasyMock and org. EasyMock respectively. Both provide the same basic functionality; however classextensions does not have quite as extensive as an API as the regular EasyMock does.
Section 10 EasyMock has a lifecycle similar to JUnit. It contains four stages.
JUnit and EasyMock cooperation
It uses a custom classloader and bytecode manipulation to enable mocking of static methods, constructors, final classes and methods, private methods, removal of static initializers and more If the thought of writing all the mock object classes you might need is intimidating, look at EasyMock, a convenient Java API for creating mock objects dynamically. Proxy, but seems like you saved us lot of trouble. Oren Gross, Mercury Interactive EasyMock can save a lot of legwork and make unit tests a lot faster to write. Moreover, it encourages us to make more frequent use of MockObjects leading to compositional and interface oriented designs. Not only is it well crafted and easy to use. It also enhances communication in the TestCase for it exposes the expected calls on the MockObject right where you need it. Dierk Koenig, Canoo AG I have been using EasyMock to unit test some web-based classes without requiring the presence of the app server and I am very impressed.
Tells JUnit a collection of classes to run. Used with the RunWith Suite. Test Class optional Timeout optional Used to indicate a test method. The class parameter is used to indicate an exception is expected to be thrown and what the exception is. The timeout parameter specifies in milliseconds how long to allow a single test to run. If the test takes longer than the timeout, it will be considered a failure. Table 3.