Andate A La Concha De Tu Madre

Test the untestable
Johan Haleby and Jan Kronquist www.powermock.org

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Audience survey
Writing unit tests? Using mock framework? Using EasyMock? Frustrated withcurrent limitations?

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Automated + isolated testing
Mock A A TestCase Code Under Test Mock B B

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Mock objects and stubsSimulated objects that mimic behavior of real objects Stubs provide canned replies Mocks verify expectations

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EasyMock
// Create a mock SomeInterface mock =createMock(SomeInterface.class); // Record behavior expect(mock.doStuff("argument")).andReturn("returnValue"); // Replay behavior replay(mock); // Executing the code we want to test assertEquals("returnValue",test.perform()); // Verify behavior verify(mock);

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Traditional assumptions
Testable = good design Testable = easy to understand Testable = limitations

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Problem - Static methods
Not possible to mock Still 3rd party libraries that use them
Eclipse, Java ME

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Problem - Static initializersYou cannot unit test a class with evil static initializer
public class EvilStaticInitializer { static { System.loadLibrary(“evil.dll”); } }

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Problem - Final class/ method
Final methods cannot be mocked Why use final?
Ensure that your classes are not misused Correct object construction

Examples: Wicket, Apache Mina

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9Problem - Private methods/state
Invocation is hard Mocking not possible State access not possible Private is used to enforce encapsulation

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Problem - Using newCode not designed for testing Not everything needs to be injected
File file = new File(fileName); if (file.exists()) { doStuff(); }

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Traditional solutions
Better...