1page.title=Testing Your Content Provider 2page.tags=testing, content provider 3trainingnavtop=true 4 5@jd:body 6 7<!-- This is the training bar --> 8<div id="tb-wrapper"> 9<div id="tb"> 10 <h2>Dependencies and Prerequisites</h2> 11 12 <ul> 13 <li>Android 2.2 (API level 8) or higher</li> 14 <li><a href="{@docRoot}tools/testing-support-library/index.html"> 15 Android Testing Support Library</a></li> 16 <li><a href="{@docRoot}tools/studio/index.html">Android Studio 1.4.1 or higher</a>.</li> 17 </ul> 18 19 <h2>This lesson teaches you to</h2> 20 21 <ol> 22 <li><a href="#build">Create Integration Tests for Content Providers</a></li> 23 <li><a href="#WhatToTest">What to Test</a></li> 24 </ol> 25 26 <h2>You should also read</h2> 27 <ul> 28 <li><a href="{@docRoot}guide/topics/providers/content-providers.html">Content Providers</a> 29 </li> 30 </ul> 31</div> 32</div> 33 34<p> 35 If you are implementing a <a href="{@docRoot}guide/topics/providers/content-providers.html"> 36 content provider</a> to store and retrieve data or to make data 37 accessible to other apps, you should test your provider to ensure that it doesn't behave in an 38 unexpected way. This lesson describes how to test public content providers, and is also 39 applicable to providers that you keep private to your own app. 40</p> 41<h2 id="build">Create Integration Tests for Content Providers</h2> 42<p> 43In Android, apps view content providers as data APIs that provide 44tables of data, with their internals hidden from view. A content provider may have many 45public constants, but it usually has few if any public methods and no public variables. 46For this reason, you should write your tests based only on the provider's public members. 47A content provider that is designed like this is offering a contract between itself and its users. 48</p> 49<p> 50Content providers let you access actual user data, so it's important to ensure 51that you test the content provider in an isolated testing environment. This approach allows you to 52only run against data dependencies set explicitly in the test case. It also means that your tests 53do not modify actual user data. For example, you should avoid writing a test that fails because 54there was data left over from a previous test. Similarly, your test should avoid adding or deleting 55actual contact information in a provider. 56</p> 57 58<p> 59To test your content provider in isolation, use the {@link android.test.ProviderTestCase2} class. 60This class allows you to use Android mock object classes such as {@link android.test.IsolatedContext} 61and {@link android.test.mock.MockContentResolver} to access file and database information without 62affecting the actual user data. 63</p> 64 65<p>Your integration test should be written as a JUnit 4 test class. To learn more about creating 66JUnit 4 test classes and using JUnit 4 assertions, see 67<a href="{@docRoot}training/testing/unit-testing/local-unit-tests.html#build"> 68Create a Local Unit Test Class</a>.</p> 69 70<p>To create an integration test for your content provider, you must perform these steps:</p> 71<ul> 72 <li>Create your test class as a subclass of {@link android.test.ProviderTestCase2}.</li> 73 <li>Add the 74{@code @RunWith(AndroidJUnit4.class)} annotation at the beginning of your test class 75definition.</li> 76 <li>Specify the 77<a href="{@docRoot}reference/android/support/test/runner/AndroidJUnitRunner.html"> 78{@code AndroidJUnitRunner}</a> class that the 79<a href="{@docRoot}tools/testing-support-library/index.html">Android Testing Support Library</a> 80provides as your default test runner. This step is described in more detail in 81<a href="{@docRoot}training/testing/start/index.html#run-instrumented-tests"> 82Getting Started with Testing</a>.</li> 83 <li>Set the {@link android.content.Context} object from the 84<a href="{@docRoot}reference/android/support/test/InstrumentationRegistry.html"> 85{@code InstrumentationRegistry}</a> class. See the snippet below for an example. 86 <pre> 87@Override 88protected void setUp() throws Exception { 89 setContext(InstrumentationRegistry.getTargetContext()); 90 super.setUp(); 91}</pre> 92 </li> 93</ul> 94 95<h3 id="ProviderTestCase2">How ProviderTestCase2 works</h3> 96<p> 97 You test a provider with a subclass of {@link android.test.ProviderTestCase2}. This base class 98 extends {@link android.test.AndroidTestCase}, so it provides the JUnit testing framework as well 99 as Android-specific methods for testing application permissions. The most important 100 feature of this class is its initialization, which creates the isolated test environment. 101</p> 102<p> 103 The initialization is done in the constructor for {@link android.test.ProviderTestCase2}, which 104 subclasses call in their own constructors. The {@link android.test.ProviderTestCase2} 105 constructor creates an {@link android.test.IsolatedContext} object that allows file and 106 database operations but stubs out other interactions with the Android system. 107 The file and database operations themselves take place in a directory that is local to the 108 device or emulator and has a special prefix. 109</p> 110<p> 111 The constructor then creates a {@link android.test.mock.MockContentResolver} to use as the 112 resolver for the test. 113</p> 114<p> 115 Lastly, the constructor creates an instance of the provider under test. This is a normal 116 {@link android.content.ContentProvider} object, but it takes all of its environment information 117 from the {@link android.test.IsolatedContext}, so it is restricted to 118 working in the isolated test environment. All of the tests done in the test case class run 119 against this isolated object. 120</p> 121 122<p> 123You run integration tests for content providers the same way as instrumented unit tests. To run the 124integration test for your content provider, follow the steps described in <a 125href="{@docRoot}training/testing/unit-testing/instrumented-unit-tests.html#run"> 126Run Instrumented Unit Tests</a>. 127</p> 128 129<h2 id="WhatToTest">What to Test</h2> 130<p> 131Here are some specific guidelines for testing content providers. 132</p> 133<ul> 134 <li> 135 Test with resolver methods: Even though you can instantiate a provider object in 136 {@link android.test.ProviderTestCase2}, you should always test with a resolver object 137 using the appropriate URI. Doing so ensures that you are testing the provider by performing 138 the same interaction that a regular application would use. 139 </li> 140 <li> 141 Test a public provider as a contract: If you intend your provider to be public and 142 available to other applications, you should test it as a contract. Some examples of how to 143 do so are as follows: 144 <ul> 145 <li> 146 Test with constants that your provider publicly exposes. For 147 example, look for constants that refer to column names in one of the provider's 148 data tables. These should always be constants publicly defined by the provider. 149 </li> 150 <li> 151 Test all the URIs that your provider offers. Your provider may offer several URIs, 152 each one referring to a different aspect of the data. 153 </li> 154 <li> 155 Test invalid URIs: Your unit tests should deliberately call the provider with an 156 invalid URI, and look for errors. A good provider design is to throw an 157 {@code IllegalArgumentException} for invalid URIs. 158 159 </li> 160 </ul> 161 </li> 162 <li> 163 Test the standard provider interactions: Most providers offer six access methods: 164 {@code query()}, {@code insert()}, {@code delete()}, {@code update()}, 165 {@code getType()}, and {@code onCreate()}. Your tests should verify that all 166 of these methods work. These methods are described in more detail in the topic 167 <a href="{@docRoot}guide/topics/providers/content-providers.html">Content Providers</a>. 168 </li> 169 <li> 170 Test business logic: If the content provider implements business logic, you should test it. 171 Business logic includes handling of invalid values, financial or arithmetic calculations, 172 elimination or combining of duplicates. 173 </li> 174</ul>