1 /*
2  * Copyright (C) 2011 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.dialer.util;
18 
19 import android.content.Context;
20 import android.content.res.Configuration;
21 import android.content.res.Resources;
22 
23 import java.util.Locale;
24 
25 /**
26  * Utility class to save and restore the locale of the system.
27  * <p>
28  * This can be used for tests that assume to be run in a certain locale, e.g., because they
29  * check against strings in a particular language or require an assumption on how the system
30  * will behave in a specific locale.
31  * <p>
32  * In your test, you can change the locale with the following code:
33  * <pre>
34  * public class CanadaFrenchTest extends AndroidTestCase {
35  *     private LocaleTestUtils mLocaleTestUtils;
36  *
37  *     &#64;Override
38  *     public void setUp() throws Exception {
39  *         super.setUp();
40  *         mLocaleTestUtils = new LocaleTestUtils(getContext());
41  *         mLocaleTestUtils.setLocale(Locale.CANADA_FRENCH);
42  *     }
43  *
44  *     &#64;Override
45  *     public void tearDown() throws Exception {
46  *         mLocaleTestUtils.restoreLocale();
47  *         mLocaleTestUtils = null;
48  *         super.tearDown();
49  *     }
50  *
51  *     ...
52  * }
53  * </pre>
54  * Note that one should not call {@link #setLocale(Locale)} more than once without calling
55  * {@link #restoreLocale()} first.
56  * <p>
57  * This class is not thread-safe. Usually its methods should be invoked only from the test thread.
58  */
59 public class LocaleTestUtils {
60     private final Context mContext;
61     private boolean mSaved;
62     private Locale mSavedContextLocale;
63     private Locale mSavedSystemLocale;
64 
65     /**
66      * Create a new instance that can be used to set and reset the locale for the given context.
67      *
68      * @param context the context on which to alter the locale
69      */
LocaleTestUtils(Context context)70     public LocaleTestUtils(Context context) {
71         mContext = context;
72         mSaved = false;
73     }
74 
75     /**
76      * Set the locale to the given value and saves the previous value.
77      *
78      * @param locale the value to which the locale should be set
79      * @throws IllegalStateException if the locale was already set
80      */
setLocale(Locale locale)81     public void setLocale(Locale locale) {
82         if (mSaved) {
83             throw new IllegalStateException(
84                     "call restoreLocale() before calling setLocale() again");
85         }
86         mSavedContextLocale = setResourcesLocale(mContext.getResources(), locale);
87         mSavedSystemLocale = setResourcesLocale(Resources.getSystem(), locale);
88         mSaved = true;
89     }
90 
91     /**
92      * Restores the previously set locale.
93      *
94      * @throws IllegalStateException if the locale was not set using {@link #setLocale(Locale)}
95      */
restoreLocale()96     public void restoreLocale() {
97         if (!mSaved) {
98             throw new IllegalStateException("call setLocale() before calling restoreLocale()");
99         }
100         setResourcesLocale(mContext.getResources(), mSavedContextLocale);
101         setResourcesLocale(Resources.getSystem(), mSavedSystemLocale);
102         mSaved = false;
103     }
104 
105     /**
106      * Sets the locale for the given resources and returns the previous locale.
107      *
108      * @param resources the resources on which to set the locale
109      * @param locale the value to which to set the locale
110      * @return the previous value of the locale for the resources
111      */
setResourcesLocale(Resources resources, Locale locale)112     private Locale setResourcesLocale(Resources resources, Locale locale) {
113         Configuration contextConfiguration = new Configuration(resources.getConfiguration());
114         Locale savedLocale = contextConfiguration.locale;
115         contextConfiguration.locale = locale;
116         resources.updateConfiguration(contextConfiguration, null);
117         return savedLocale;
118     }
119 }
120