如何开始：使用 AssertJ Swing 测试 Java Swing GUI

在使用 Swing 开发 Java 桌面应用程序时，我需要直接测试 UI，而不仅仅是通过单元测试测试底层控制器/模型类。

This 答案（关于“基于 Swing 的应用程序的最佳测试工具是什么？”） https://stackoverflow.com/a/80222/5127499建议使用FEST https://code.google.com/archive/p/fest/，不幸的是已经停产了。 然而，有一些项目是从 FEST 离开的地方继续进行的。特别是其中一个（在本节中提到answer https://stackoverflow.com/questions/91179/automated-tests-for-java-swing-guis/32771043）引起了我的注意，因为我之前在单元测试中使用过它：AssertJ https://joel-costigliola.github.io/assertj/.

显然有断言J Swing https://joel-costigliola.github.io/assertj/assertj-swing.html，它基于 FEST，并提供了一些编写 Swing UI 测试的易于使用的方法。 但是，进行初始/工作设置仍然很麻烦，因为很难说从哪里开始。

如何为以下示例 UI 创建最小的测试设置（仅包含两个类）？

约束：Java SE、Swing UI、Maven 项目、JUnit

public class MainApp {

    /**
     * Run me, to use the app yourself.
     *
     * @param args ignored
     */
    public static void main(String[] args) {
        MainApp.showWindow().setSize(600, 600);
    }

    /**
     * Internal standard method to initialize the view, returning the main JFrame (also to be used in automated tests).
     *
     * @return initialized JFrame instance
     */
    public static MainWindow showWindow() {
        MainWindow mainWindow = new MainWindow();
        mainWindow.setVisible(true);
        return mainWindow;
    }
}

public class MainWindow extends JFrame {

    public MainWindow() {
        super("MainWindow");
        this.setContentPane(this.createContentPane());
    }

    private JPanel createContentPane() {
        JTextArea centerArea = new JTextArea();
        centerArea.setName("Center-Area");
        centerArea.setEditable(false);
        JButton northButton = this.createButton("North", centerArea);
        JButton southButton = this.createButton("South", centerArea);
        JPanel contentPane = new JPanel(new BorderLayout());
        contentPane.add(centerArea);
        contentPane.add(northButton, BorderLayout.NORTH);
        contentPane.add(southButton, BorderLayout.SOUTH);
        return contentPane;
    }

    private JButton createButton(final String text, final JTextArea centerArea) {
        JButton button = new JButton(text);
        button.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent event) {
                centerArea.setText(centerArea.getText() + text + ", ");
            }
        });
        return button;
    }
}

我知道这个问题本身非常广泛，因此我自己提供了一个答案 - 展示这个特定的例子。

TL;DR：示例项目可以在GitHub https://github.com/CarstenWickner/assertj-swing-example.

假设这是一个 Maven 项目，您首先需要添加至少两个依赖项：

1. 单元测试框架（例如这里junit– 但也可以使用testng)
2. 配套的AssertJ Swing图书馆（例如这里assertj-swing-junit)

它可能看起来像这样（在你的pom.xml:

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.assertj</groupId>
    <artifactId>assertj-swing-junit</artifactId>
    <version>1.2.0</version>
    <scope>test</scope>
</dependency>

其次，我通常选择一个基本测试类来将大部分测试设置与实际测试分开：

/**
 * Base class for all my UI tests taking care of the basic setup.
 */
public class AbstractUiTest extends AssertJSwingTestCaseTemplate {

    /**
     * The main entry point for any tests: the wrapped MainWindow.
     */
    protected FrameFixture frame;

    /**
     * Installs a {@link FailOnThreadViolationRepaintManager} to catch violations of Swing threading rules.
     */
    @BeforeClass
    public static final void setUpOnce() {
        // avoid UI test execution in a headless environment (e.g. when building in CI environment like Jenkins or TravisCI)
        Assume.assumeFalse("Automated UI Test cannot be executed in headless environment", GraphicsEnvironment.isHeadless());
        FailOnThreadViolationRepaintManager.install();
    }

    /**
     * Sets up this test's fixture, starting from creation of a new <code>{@link Robot}</code>.
     *
     * @see #setUpRobot()
     * @see #onSetUp()
     */
    @Before
    public final void setUp() {
        // call provided AssertJSwingTestCaseTemplate.setUpRobot()
        this.setUpRobot();
        // initialize the graphical user interface
        MainWindow mainWindow = GuiActionRunner.execute(new GuiQuery<MainWindow>() {

            @Override
            protected MainWindow executeInEDT() throws Exception {
                return MainApp.showWindow();
            }
        });
        this.frame = new FrameFixture(this.robot(), mainWindow);
        this.frame.show();
        this.frame.resizeTo(new Dimension(600, 600));
        onSetUp();
    }

    /**
     * Subclasses that need to set up their own test fixtures in this method. Called as <strong>last action</strong> during {@link #setUp()}.
     */
    protected void onSetUp() {
        // default: everything is already set up
    }

    /*****************************************************************************************
     * Here you could insert further helper methods, e.g. frequently used component matchers *
     *****************************************************************************************/

    /**
     * Cleans up any resources used in this test. After calling <code>{@link #onTearDown()}</code>, this method cleans up resources used by this
     * test's <code>{@link Robot}</code>.
     *
     * @see #cleanUp()
     * @see #onTearDown()
     */
    @After
    public final void tearDown() {
        try {
            onTearDown();
            this.frame = null;
        } finally {
            cleanUp();
        }
    }

    /**
     * Subclasses that need to clean up resources can do so in this method. Called as <strong>first action</strong> during {@link #tearDown()}.
     */
    protected void onTearDown() {
        // default: nothing more to tear down
    }
}

实际的测试类可能如下所示：

public class MainWindowTest extends AbstractUiTest {

    private JButtonFixture northButtonFixture;
    private JButtonFixture southButtonFixture;

    @Override
    protected void onSetUp() {
        this.northButtonFixture = this.frame.button(JButtonMatcher.withText("North"));
        this.southButtonFixture = this.frame.button(JButtonMatcher.withText("South"));
    }

    @Test
    public void testWithDifferingComponentMatchers() {
        // use JTextComponentMatcher.any() as there is only one text input
        this.frame.textBox(JTextComponentMatcher.any()).requireVisible().requireEnabled().requireNotEditable().requireEmpty();
        this.northButtonFixture.requireVisible().requireEnabled().click();
        // use value assigned in MainWindow class via JTextArea.setName("Center-Area") to identify component here
        this.frame.textBox("Center-Area").requireText("North, ");

        this.southButtonFixture.requireVisible().requireEnabled().click();
        // write our own matcher
        JTextComponentFixture centerArea = this.frame.textBox(new GenericTypeMatcher(JTextArea.class, true) {
            @Override
            protected boolean isMatching(Component component) {
                return true;
            }
        });
        centerArea.requireVisible().requireEnabled().requireText("North, South, ");
    }

    @Override
    protected void onTearDown() {
        this.northButtonFixture = null;
        this.southButtonFixture = null;
    }
}

一旦您在项目中完成了这样的基本设置，您可能需要研究各种类型的组件匹配器，并可能引入一些组件匹配器setName()调用您想要测试的各种组件，以使您的生活更轻松。