我参考了谷歌的一个关于如何测试你的SharedPreferences代码的示例，创建了一个SharedPreferencesHelper类：
sharedPreferences 的键 - 下面是该类的一部分代码片段: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();
}
当在这里使用他们的
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。
以下是该类的一部分内容：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，就像通常使用getString()一样。mSharedPreferences.getString(context.getString(R.string.name),"");
然而，我已经阅读到context.getString不可能使用，因为它是一个final方法，mockito无法模拟final方法:
Mockito - Overriding a method that takes primitive parameters
那么，我如何使用mockito来单元测试任何带有getString的方法呢？任何带有getString的方法都将无法工作，我的单元测试将会失败。
这是我为SharedPreferences编写的类，我想用getStrings编写的sharedPreferences键来测试它：
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，因为我在我的SharedPreferencesHelper类中使用了getString。如果我硬编码键，就不会出现错误，即：
public String fetchName() {
// Start a SharedPreferences transaction.
return mSharedPreferences.getString("name","");
}
在代码中不应该硬编码字符串，那么我该如何解决这个困境？
getString总是返回null（使用Gradle 3.3.2和Mockito 2.23.4进行测试）。这可能解释了为什么（他们建议为Android制作的Mockito变体）：https://medium.com/androiddevelopers/mock-final-and-static-methods-on-android-devices-b383da1363ad - user905686