1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file 5 * except in compliance with the License. You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software distributed under the 10 * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 11 * KIND, either express or implied. See the License for the specific language governing 12 * permissions and limitations under the License. 13 */ 14 15 package android.testing; 16 17 import static org.mockito.Mockito.mock; 18 import static org.mockito.Mockito.withSettings; 19 20 import android.content.Context; 21 import android.content.res.Resources; 22 import android.util.Log; 23 import android.util.SparseArray; 24 25 import org.mockito.invocation.InvocationOnMock; 26 27 /** 28 * Provides a version of Resources that defaults to all existing resources, but can have ids 29 * changed to return specific values. 30 * <p> 31 * TestableResources are lazily initialized, be sure to call 32 * {@link TestableContext#ensureTestableResources} before your tested code has an opportunity 33 * to cache {@link Context#getResources}. 34 * </p> 35 */ 36 public class TestableResources { 37 38 private static final String TAG = "TestableResources"; 39 private final Resources mResources; 40 private final SparseArray<Object> mOverrides = new SparseArray<>(); 41 42 /** Creates a TestableResources instance that calls through to the given real Resources. */ TestableResources(Resources realResources)43 public TestableResources(Resources realResources) { 44 mResources = mock(Resources.class, withSettings() 45 .spiedInstance(realResources) 46 .defaultAnswer(this::answer)); 47 } 48 49 /** 50 * Gets the implementation of Resources that will return overridden values when called. 51 */ getResources()52 public Resources getResources() { 53 return mResources; 54 } 55 56 /** 57 * Sets the return value for the specified resource id. 58 * <p> 59 * Since resource ids are unique there is a single addOverride that will override the value 60 * whenever it is gotten regardless of which method is used (i.e. getColor or getDrawable). 61 * </p> 62 * @param id The resource id to be overridden 63 * @param value The value of the resource, null to cause a {@link Resources.NotFoundException} 64 * when gotten. 65 */ addOverride(int id, Object value)66 public void addOverride(int id, Object value) { 67 mOverrides.put(id, value); 68 } 69 70 /** 71 * Removes the override for the specified id. 72 * <p> 73 * This should be called over addOverride(id, null), because specifying a null value will 74 * cause a {@link Resources.NotFoundException} whereas removing the override will actually 75 * switch back to returning the default/real value of the resource. 76 * </p> 77 * @param id 78 */ removeOverride(int id)79 public void removeOverride(int id) { 80 mOverrides.remove(id); 81 } 82 answer(InvocationOnMock invocationOnMock)83 private Object answer(InvocationOnMock invocationOnMock) throws Throwable { 84 try { 85 int id = invocationOnMock.getArgument(0); 86 int index = mOverrides.indexOfKey(id); 87 if (index >= 0) { 88 Object value = mOverrides.valueAt(index); 89 if (value == null) throw new Resources.NotFoundException(); 90 return value; 91 } 92 } catch (Resources.NotFoundException e) { 93 // Let through NotFoundException. 94 throw e; 95 } catch (Throwable t) { 96 // Generic catching for the many things that can go wrong, fall back to 97 // the real implementation. 98 Log.i(TAG, "Falling back to default resources call " + t); 99 } 100 return invocationOnMock.callRealMethod(); 101 } 102 } 103