Mockito:我如何在mockito中使用getString？

Question

我从谷歌的示例中获得了如何SharedPreferences通过创建SharedPreferencesHelper类来测试代码的灵感:

https://github.com/googlesamples/android-https://github.com/googlesamples/android-testing/blob/master/unit/BasicSample/app/src/main/java/com/example/android/testing/单元测试/ BasicSample/SharedPreferencesHelper.java

您可以看到该类使用类中硬编码的实际字符串作为键的sharedPreferences- 这是类的提取:

public class SharedPreferencesHelper {

    // Keys for saving values in SharedPreferences.
    static final String KEY_NAME = "key_name";
    static final String KEY_DOB = "key_dob_millis";
    static final String KEY_EMAIL = "key_email";

    public boolean savePersonalInfo(SharedPreferenceEntry sharedPreferenceEntry){
        // Start a SharedPreferences transaction.
        SharedPreferences.Editor editor = mSharedPreferences.edit();
        editor.putString(KEY_NAME, sharedPreferenceEntry.getName());
        editor.putLong(KEY_DOB, sharedPreferenceEntry.getDateOfBirth().getTimeInMillis());
        editor.putString(KEY_EMAIL, sharedPreferenceEntry.getEmail());

        // Commit changes to SharedPreferences.
        return editor.commit();
    }

在SharedPreferencesHelperTest这里使用他们的类测试时,他们sharedPreferences使用上面类中定义的相同变量访问模拟:

https://github.com/googlesamples/android-testing/blob/master/unit/BasicSample/app/src/test/java/com/example/android/testing/unittesting/BasicSample/SharedPreferencesHelperTest.java

该类的摘录显示如下:

when(mMockSharedPreferences.getString(eq(SharedPreferencesHelper.KEY_NAME), anyString()))
            .thenReturn(mSharedPreferenceEntry.getName());
    when(mMockSharedPreferences.getString(eq(SharedPreferencesHelper.KEY_EMAIL), anyString()))
            .thenReturn(mSharedPreferenceEntry.getEmail());
    when(mMockSharedPreferences.getLong(eq(SharedPreferencesHelper.KEY_DOB), anyLong()))
            .thenReturn(mSharedPreferenceEntry.getDateOfBirth().getTimeInMillis());

谷歌这样做的方式允许他们绕过使用a context从string.xml资源文件中拉出一个字符串并在内部查询它的问题,sharedPreferences就像通常假设通过使用它发生一样getString(),即:

mSharedPreferences.getString(context.getString(R.string.name),"");

但是,我已经读过它是不可能使用的,context.getString因为它是最终方法而且mockito不能模拟最终方法:

Mockito - 覆盖采用原始参数的方法

然后,我如何使用mockito对任何方法进行单元测试getString？任何方法getString都不起作用,我的单元测试将失败.

这是我写的课程,我SharedPreferences想用以下代码sharedPreferences编写的密钥进行测试getStrings:

public class SharedPreferencesHelper {

    // The injected SharedPreferences implementation to use for persistence.
    private final SharedPreferences mSharedPreferences;
    private Context context;

    public SharedPreferencesHelper(SharedPreferences sharedPreferences, Context context) {
        mSharedPreferences = sharedPreferences;
        this.context = context;
    }

    public boolean saveName(String name) {
        // Start a SharedPreferences transaction.
        SharedPreferences.Editor editor = mSharedPreferences.edit();
        editor.putString(context.getString(R.string.name), name);
        return editor.commit();
    }

    public String fetchName() {
        // Start a SharedPreferences transaction.
        return mSharedPreferences.getString(context.getString(R.string.name),"");
    }

    public boolean saveGender(String gender) {
        SharedPreferences.Editor editor = mSharedPreferences.edit();
        editor.putString(context.getString(R.string.gender), gender);
        return editor.commit();
    }

}

这是我为上述类编写的测试 - 它与google的SharedPreferencesHelperTest非常相似:

@RunWith(MockitoJUnitRunner.class)
public class SharedPreferencesHelperTest {

    private static final String TEST_NAME = "Test name";

    private SharedPreferencesHelper mMockSharedPreferencesHelper;

    @Mock
    SharedPreferences mMockSharedPreferences;
    @Mock
    SharedPreferences.Editor mMockEditor;
    @Mock
    MockContext context;

    @Before
    public void setUp() throws Exception {
        // Create a mocked SharedPreferences.
        mMockSharedPreferencesHelper = createMockSharedPreference();
    }

    @Test
    public void testSaveName() throws Exception {
        boolean success = mMockSharedPreferencesHelper.saveName(TEST_NAME);
        Timber.e("success " + success);
        assertThat("Checking that name was saved... returns true = " + success,
                success, is(true));
        String name = mMockSharedPreferencesHelper.fetchName();
        Timber.e("name " + name);
        assertThat("Checking that name has been persisted and read correctly " + name,
                TEST_NAME,
                is(name));
    }

    /**
     * Creates a mocked SharedPreferences.
     */
    private SharedPreferencesHelper createMockSharedPreference() {
        // Mocking reading the SharedPreferences as if mMockSharedPreferences was previously written
        // correctly.
        when(mMockSharedPreferences.getString(Matchers.eq("name"), anyString()))
                .thenReturn(TEST_NAME);
        when(mMockSharedPreferences.getString(Matchers.eq("gender"), anyString()))
                .thenReturn("M");
        // Mocking a successful commit.
        when(mMockEditor.commit()).thenReturn(true);
        // Return the MockEditor when requesting it.
        when(mMockSharedPreferences.edit()).thenReturn(mMockEditor);
        return new SharedPreferencesHelper(mMockSharedPreferences, context);
    }
}

运行测试失败,因为我getString在SharedPreferencesHelper课堂上使用过.如果我对密钥进行硬编码,我将不会收到错误,即:

public String fetchName() {
    // Start a SharedPreferences transaction.
    return mSharedPreferences.getString("name","");
}

不应该在代码中对字符串进行硬编码,那么如何解决这个难题呢？

Answer 1

您可以通过不使用Context获取字符串资源来解决此问题,而是使用Resources类.Resources有相同的getString方法,但它不是最终的.

https://developer.android.com/reference/android/content/res/Resources.html#getString(int)

或者你可以尝试Robolectric,它可以解决这个问题,因为它们实现了上下文.

http://robolectric.org/