我从google的示例中获得了灵感，通过创建一个SharedPreferencesHelper类来测试SharedPreferences代码：
https://github.com/googlesamples/android-https://github.com/googlesamples/android-testing/blob/master/unit/BasicSample/app/src/main/java/com/example/android/testing/unittesting/BasicSample/SharedPreferencesHelper.java
可以看到，该类使用类中硬编码的实际字符串作为sharedPreferences的键--下面是该类的摘录：

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();
    }

在这里使用SharedPreferencesHelperTest类进行测试时，他们使用上述类中定义的相同变量访问模拟的sharedPreferences：
https://github.com/googlesamples/android-testing/blob/master/unit/BasicSample/app/src/test/java/com/example/android/testing/unittesting/BasicSample/SharedPreferencesHelperTest.java
该类的摘录如下所示：

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());

google这样做的方式允许他们绕过使用context从string.xml资源文件中提取字符串并在sharedPreferences中查询它的问题，就像使用getString()通常假设的那样，即：

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

但是，我读到过不能使用context.getString，因为它是final方法，mockito不能模拟final方法：
Mockito -重写接受基元参数的方法
然后我如何使用mockito对任何使用getString的方法进行单元测试？任何使用getString的方法都将无法工作，我的单元测试将失败。
这是我为SharedPreferences编写的类，我想用getStrings编写的sharedPreferences密钥测试它：

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();
    }

}

这是我为上面的类编写的测试--它非常类似于google的SharedPreferencesHelperTest：

@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，因为我在SharedPreferencesHelper类中使用了getString。如果我硬编码密钥，我将不会得到错误，即：

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

不应该在代码中硬编码字符串，那么我该如何解决这个难题呢？