【发布时间】：2016-07-10 20:40:52
【问题描述】：
我从 google 的示例中获得了关于如何通过创建 SharedPreferencesHelper 类来测试您的 SharedPreferences 代码的灵感：
您可以看到该类使用类中硬编码的实际字符串作为sharedPreferences 的键 - 这是该类的摘录：
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：
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());
谷歌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，就像它是如何一样通常假设使用getString() 发生，即：
mSharedPreferences.getString(context.getString(R.string.name),"");
但是，我读到不能使用context.getString，因为它是一种最终方法，而mockito 不能模拟最终方法：
Mockito - Overriding a method that takes primitive parameters
然后如何使用 mockito 对 getString 的任何方法进行单元测试？任何带有getString 的方法都不起作用，我的单元测试将失败。
这是我为SharedPreferences 编写的课程，我想用sharedPreferences 用getStrings 编写的键对其进行测试：
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();
}
}
这是我为上述课程编写的测试 - 它与谷歌的 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 SharedPreferencesHelper 类中使用了 getString。如果我对密钥进行硬编码，则不会出现错误，即：
public String fetchName() {
// Start a SharedPreferences transaction.
return mSharedPreferences.getString("name","");
}
不应在代码中硬编码字符串，那么我该如何解决这个难题？
【问题讨论】：
标签： android unit-testing mockito android-context