android - 无法监视 Android 类

Question

我有一个像这样的简单的 android 常量类:

public class Consts extends BaseConstants {

    public static final String SCHEME = "http";

    // Tag used to cancel the request
    public static final String TAG_JSON = "json_obj_req";
}

里面没有别的东西，所以模拟起来应该很简单。我在我的测试用例中调用它:

Mockito.spy(Consts.class); ...这是失败的。下面是测试用例文件:

public class ApplicationTest extends ActivityInstrumentationTestCase2<MainActivity> {

  MainActivity mActivity;

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

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

      setActivityInitialTouchMode(false);

      mActivity = getActivity();
  }

  public void testUrlValid() {
      Mockito.spy(Consts.class);
  }

}

这是测试用例的 logcat 输出:

Running tests
Test running started
org.mockito.exceptions.base.MockitoException:
Cannot mock/spy class java.lang.Class
Mockito cannot mock/spy following:
- final classes
- anonymous classes
- primitive types

--------更新:

我想监视我的 mainActivity 类，但我得到了相同的 Mockito 异常:这是我正在测试的类:

import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;


public class MainActivity extends ListPageActivity {

  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      if (savedInstanceState == null) {
          getFragmentManager().beginTransaction()
                .add(R.id.container, new SummaryFragment(),"SummaryFragment")
                .commit();
      }

      loadBrandSound();

     if (!isNetworkAvailable())
          showToast(getString(R.string.no_network));
  }

  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
      // Inflate the menu; this adds items to the action bar if it is   present.
      getMenuInflater().inflate(R.menu.menu_main, menu);
      return true;
  }

  @Override
  public boolean onOptionsItemSelected(MenuItem item) {
      // Handle action bar item clicks here. The action bar will
      // automatically handle clicks on the Home/Up button, so long
      // as you specify a parent activity in AndroidManifest.xml.
      int id = item.getItemId();

      //noinspection SimplifiableIfStatement
      if (id == R.id.action_settings) {
          return true;
      }

      return super.onOptionsItemSelected(item);
  }
}

这是我的简单测试用例:

import android.test.ActivityInstrumentationTestCase2;
import android.widget.Button;
import android.widget.EditText;

import org.mockito.Mockito;

public class ApplicationTest extends ActivityInstrumentationTestCase2<MainActivity> {

    MainActivity mActivity;
    private Button goBtn;
    private EditText et_query;
    private RecyclerListAdapter mAdapter;

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

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

        setActivityInitialTouchMode(false);

        mActivity = getActivity();

        goBtn=(Button)mActivity.findViewById(
                R.id.btn_go);
        et_query = (EditText)mActivity.findViewById(R.id.et_query);
    }

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

    public void testPreconditions() {
        assertTrue(mActivity.isNetworkAvailable());
        isLayoutValid();
    }

    public void isLayoutValid(){
        assertNotNull(goBtn);
    }

    public void testSomething(){
        Mockito.spy(MainActivity.class);
    }

}

为什么它在 spy 线上失败了？这是日志:

    Running tests
Test running started
org.mockito.exceptions.base.MockitoException:
Cannot mock/spy class java.lang.Class
Mockito cannot mock/spy following:
- final classes
- anonymous classes
- primitive types
at mypackage.ApplicationTest.testSomething(ApplicationTest.java:65)
at java.lang.reflect.Method.invokeNative(Native Method)
at android.test.InstrumentationTestCase.runMethod(InstrumentationTestCase.java:214)
at android.test.InstrumentationTestCase.runTest(InstrumentationTestCase.java:199)
at android.test.ActivityInstrumentationTestCase2.runTest(ActivityInstrumentationTestCase2.java:192)
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:1729)

Finish

Answer 1

不同于Mockito.mock(Class<T> clazz) , Mockito.spy(T instance)举个例子。但是，两者都返回一个实例。您要替换静态字段，而不是实例方法。

Mockito 不能模拟静态成员或最终类，因为它主要通过创建匿名代理实现或子类来工作。子类不能覆盖静态方法或扩展最终类，因此 Java 编译器采用了一种跳过任何 Mockito 提供的实现的快捷方式。 (对于静态最终常量尤其如此，它们是 inlined at compile time 。)

虽然PowerMockito可以重写被测系统代码以模拟最终和静态方法调用，它对字段没有帮助。额外的间接级别可能是更好的解决方案。

public class MyApplication extends Application {
  public boolean isUrlValid(String url) {
    return isUrlValid(url, Consts.SCHEME, Consts.TAG_JSON);
  }

  static boolean isUrlValid(String url, String scheme, String jsonTag) {
    // ...
  }
}

public class MyApplicationTest {
  @Test public void urlValidShouldWork() {
    assertTrue(MyApplication.isUrlValid(VALID_URL, "fakescheme", "faketag");
  }
}

作为替代方案，让 Consts 根据访问器方法 (getScheme) 而不是字段 (scheme) 进行操作。像 ProGuard 这样的工具通常可以内联简单的方法调用，因此它在生产中不应该变得更慢或更冗长，而且您将有更多机会在测试中替换实现。有关在测试中插入/注入(inject)模拟实现的更多技术，see this SO question .