错误"在Junit测试中没有公共TestCase(String name)或TestCase()

Question

我是junit测试android的初学者.我正在关注本教程,但得到了这个错误

junit.framework.AssertionFailedError: Class com.example.projectfortest.test.MainActivityTest has no public constructor TestCase(String name) or TestCase()
at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:191)
at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:176)
at android.test.InstrumentationTestRunner.onStart(InstrumentationTestRunner.java:554)
at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1701)

这是我的代码:

public class MainActivityTest extends
        ActivityInstrumentationTestCase2<MainActivity> {

    private MainActivity mMainActivity;
    private TextView mFirstTestText;
    private String expected, actual;

    public MainActivityTest(Class<MainActivity> activityClass) {
        super(activityClass);
    }

    @Override
    protected void setUp() throws Exception {
        super.setUp();

        mMainActivity = getActivity();
        mFirstTestText = (TextView) mMainActivity.findViewById(R.id.txt1);

        expected = mMainActivity.getString(R.string.txt1_test);
        actual = mFirstTestText.getText().toString();
    }

    public void testPreconditions() {
        assertNotNull("mMainActivity is null", mMainActivity);
        assertNotNull("mFirstTestText is null", mFirstTestText);
    }

    public void testMyFirstTestTextView_labelText() {
        assertEquals(expected, actual);
    }
}

我的代码中没有看到任何错误.请帮忙

Answer 1

正如Exception所说,为您的类添加一个默认的构造函数.这是测试框架初始化所必需的.替换你的构造函数:

public MainActivityTest(Class<MainActivity> activityClass) {
    super(activityClass);
}

通过以下方式:

public MainActivityTest() {
    super(MainActivity.class);
}

此构造函数没有框架所需的参数,并显示在教程的代码清单中: