JUnit4.5和官方文档

## Summary of Changes in version 4.5 ## ### Categories ### Each test method and test class can be annotated as belonging to a _category_: public static class SomeUITests { @Category(UserAvailable.class) @Test public void askUserToPressAKey() { } @Test public void simulatePressingKey() { } } @Category(InternetConnected.class) public static class InternetTests { @Test public void pingServer() { } } To run all of the tests in a particular category, you must currently explicitly create a custom request: new JUnitCore().run(Request.aClass(SomeUITests.class).inCategories(UserAvailable.class)); This feature will very likely be improved before the final release of JUnit 4.5 ### Theories ### - `@Before` and `@After` methods are run before and after each set of attempted parameters on a Theory, and each set of parameters is run on a new instance of the test class. - Exposed API's `ParameterSignature.getType()` and `ParameterSignature.getAnnotations()` - An array of data points can be introduced by a field or method marked with the new annotation `@DataPoints` - The Theories custom runner has been refactored to make it easier to extend ### JUnit 4 Runner API ### - There has been a drastic rewrite of the API for custom Runners in 4.5. This needs to be written up separately before release. - Tests with failed assumptions are now marked as Ignored, rather than silently passing. This may change behavior in some client tests, and also will require some new support on the part of IDE's. ## Summary of Changes in version 4.4 ## JUnit is designed to efficiently capture developers' intentions about their code, and quickly check their code matches those intentions. Over the last year, we've been talking about what things developers would like to say about their code that have been difficult in the past, and how we can make them easier. [Download][] [Download]: http://sourceforge.net/project/showfiles.php?group_id=15278 ### assertThat ### Two years ago, Joe Walnes built a [new assertion mechanism][walnes] on top of what was then [JMock 1][]. The method name was `assertThat`, and the syntax looked like this: [walnes]: http://joe.truemesh.com/blog/000511.html [JMock 1]: http://www.jmock.org/download.html assertThat(x, is(3)); assertThat(x, is(not(4))); assertThat(responseString, either(containsString("color")).or(containsString("colour"))); assertThat(myList, hasItem("3")); More generally: assertThat([value], [matcher statement]); Advantages of this assertion syntax include: - More readable and typeable: this syntax allows you to think in terms of subject, verb, object (assert "x is 3") rather than `assertEquals`, which uses verb, object, subject (assert "equals 3 x") - Combinations: any matcher statement `s` can be negated (`not(s)`), combined (`either(s).or(t)`), mapped to a collection (`each(s)`), or used in custom combinations (`afterFiveSeconds(s)`) - Readable failure messages. Compare assertTrue(responseString.contains("color") || responseString.contains("colour")); // ==> failure message: // java.lang.AssertionError: assertThat(responseString, anyOf(containsString("color"), containsString("colour"))); // ==> failure message: // java.lang.AssertionError: // Expected: (a string containing "color" or a string containing "colour") // got: "Please choose a font" - Custom Matchers. By implementing the `Matcher` interface yourself, you can get all of the above benefits for your own custom assertions. - For a more thorough description of these points, see [Joe Walnes's original post][walnes]. We have decided to include this API directly in JUnit. It's an extensible and readable syntax, and it enables new features, like [assumptions][] and [theories][]. [assumptions]: #assumptions [theories]: #theories Some notes: - The old assert methods are never, ever, going away. Developers may continue using the old `assertEquals`, `assertTrue`, and so on. - The second parameter of an `assertThat` statement is a `Matcher`. We include the Matchers we want as static imports, like this: import static org.hamcrest.CoreMatchers.is; or: import static org.hamcrest.CoreMatchers.*; - Manually importing `Matcher` methods can be frustrating. [Eclipse 3.3][] includes the ability to define "Favorite" classes to import static methods from, which makes it easier (Search for "Favorites" in the Preferences dialog). We expect that support for static imports will improve in all Java IDEs in the future. [Eclipse 3.3]: http://www.eclipse.org/downloads/ - To allow compatibility with a wide variety of possible matchers, we have decided to include the classes from hamcrest-core, from the [Hamcrest][] project. This is the first time that third-party classes have been included in JUnit. [Hamcrest]: http://code.google.com/p/hamcrest/ - JUnit currently ships with a few matchers, defined in `org.hamcrest.CoreMatchers` and `org.junit.matchers.JUnitMatchers`. To use many, many more, consider downloading the [full hamcrest package][]. [full hamcrest package]: http://hamcrest.googlecode.com/files/hamcrest-all-1.1.jar - JUnit contains special support for comparing string and array values, giving specific information on how they differ. This is not yet available using the `assertThat` syntax, but we hope to bring the two assert methods into closer alignment in future releases. <a name="assumptions" /> ### Assumptions ### Ideally, the developer writing a test has control of all of the forces that might cause a test to fail. If this isn't immediately possible, making dependencies explicit can often improve a design. For example, if a test fails when run in a different locale than the developer intended, it can be fixed by explicitly passing a locale to the domain code. However, sometimes this is not desirable or possible. It's good to be able to run a test against the code as it is currently written, implicit assumptions and all, or to write a test that exposes a known bug. For these situations, JUnit now includes the ability to express "assumptions": import static org.junit.Assume.* @Test public void filenameIncludesUsername() { assumeThat(File.separatorChar, is('/')); assertThat(new User("optimus").configFileName(), is("configfiles/optimus.cfg")); } @Test public void correctBehaviorWhenFilenameIsNull() { assumeTrue(bugFixed("13356")); // bugFixed is not included in JUnit assertThat(parse(null), is(new NullDocument())); } With this release, a failed assumption will lead to the test being marked as passing, regardless of what the code below the assumption may assert. In the future, this may change, and a failed assumption may lead to the test being ignored: however, third-party runners do not currently allow this option. We have included `assumeTrue` for convenience, but thanks to the inclusion of Hamcrest, we do not need to create `assumeEquals`, `assumeSame`, and other analogues to the `assert*` methods. All of those functionalities are subsumed in `assumeThat`, with the appropriate matcher. A failing assumption in a `@Before` or `@BeforeClass` method will have the same effect as a failing assumption in each `@Test` method of the class. <a name="theories" /> ### Theories ### More flexible and expressive assertions, combined with the ability to state assumptions clearly, lead to a new kind of statement of intent, which we call a "Theory". A test captures the intended behavior in one particular scenario. A theory captures some aspect of the intended behavior in possibly infinite numbers of potential scenarios. For example: @RunWith(Theories.class) public class UserTest { @DataPoint public static String GOOD_USERNAME = "optimus