Testing 测试

Testing is critical to your software. These packages help make it easier.

测试对于软件来说非常重要，这些包可以使之变得更加容易。

jUnit 4

jUnit needs no introduction. It's the standard tool for unit testing in Java.

jUnit无需再做介绍，它已经是Java中的标准单元测试工具了。

But you're probably not using jUnit to its full potential. jUnit supports parametrized tests, rules to stop you from writing so much boilerplate, theories to randomly test certain code, and assumptions.

但是你有可能发挥出jUnit的全部潜能。jUnit支持参数化的测试]、让你免于编写过多的样板文件的规则、随机测试确定代码的理论，以及假设]

jMock

If you've done your dependency injection, this is where it pays off: mocking out code which has side effects (like talking to a REST server) and still asserting behavior of code that calls it.

如果你已经完成了依赖注入，那么这里就有一个陷阱（-。-）：Mock出具有副作用的代码（就像REST服务里所说的那样）和依然判断所调用代码的行为。

jMock is the standard mocking tool for Java. It looks like this:

jMock是用于Java的标准Mock工具，像这样：

public class FooWidgetTest {
    private Mockery context = new Mockery();

    @Test
    public void basicTest() {
        final FooWidgetDependency dep = context.mock(FooWidgetDependency.class);

        context.checking(new Expectations() {{
            oneOf(dep).call(with(any(String.class)));
            atLeast(0).of(dep).optionalCall();
        }});

        final FooWidget foo = new FooWidget(dep);

        Assert.assertTrue(foo.doThing());
        context.assertIsSatisfied();
    }
}

This sets up a FooWidgetDependency via jMock and then adds expectations. We expect that dep's call method will be called once with some String and that dep's optionalCall method will be called zero or more times.

这里通过jMock设置了一个FooWidgetDependency，然后添加了一些预期行为。我们期望dep的call方法就会和字符串一样至少被调用一次，dep的optionalCall方法则可以被调用0次或者更多次。

If you have to set up the same dependency over and over, you should probably put that in a test fixture and put assertIsSatisfied in an @After fixture.

如果你不得不反复设置同样的依赖，也许你就可以讲它放到一个测试fixture，然后将assertIsSatisfied放到一个@Afterfixture里。

AssertJ

Do you ever do this with jUnit?

你真的会用jUnit这样做？

final List<String> result = some.testMethod();
assertEquals(4, result.size());
assertTrue(result.contains("some result"));
assertTrue(result.contains("some other result"));
assertFalse(result.contains("shouldn't be here"));

This is just annoying boilerplate. AssertJ solves this. You can transform the same code into this:

这就是非常讨厌的一种样板，AssertJ可以解决它，你可以将同样的代码改成这样：

assertThat(some.testMethod()).hasSize(4)
                             .contains("some result", "some other result")
                             .doesNotContain("shouldn't be here");

This fluent interface makes your tests more readable. What more could you want?

流畅的接口可以让你的测试更具有可读性，夫复何求？