android - 如何使用内容解析器/提供者测试类？

Question

我正在尝试测试查询内容解析器的类。

我想使用 MockContentResolver 和模拟 query 方法。

问题是这个方法是最终的。我应该怎么办？使用模拟框架？模拟其他类(class)？提前致谢。

public class CustomClass {

    private ContentResolver mContentResolver;

    public CustomClass(ContentResolver contentResolver) {
        mContentResolver = contentResolver;
    }

    public String getConfig(String key) throws NoSuchFieldException {
        String value = null;

            Cursor cursor = getContentResolver().query(...);
            if (cursor.moveToFirst()) {
                //...
            }
        //..
    }
}

Answer 1

这是一个示例测试，它使用 getContentResolver().query 从内容提供者返回模拟数据。

它应该适用于任何内容提供者，只需进行一些修改，但此示例模拟从联系人内容提供者返回的电话号码

一般步骤如下:

1. 使用 MatrixCursor 创建适当的游标
2. 扩展 MockContentProvider 以返回创建的游标
3. 使用 addProvider 和 setContentResolver 将提供程序添加到 MockContentResolver
4. 将 MockContentResolver 添加到扩展的 MockContext
5. 将上下文传递给被测类

因为查询是 final方法，所以您不仅需要模拟 MockContentProvider，还需要模拟 MockContentResolver。否则在查询方法中调用acquireProvider时会报错。

示例代码如下:

public class MockContentProviderTest extends AndroidTestCase{
    public void testMockPhoneNumbersFromContacts(){
        //Step 1: Create data you want to return and put it into a matrix cursor
        //In this case I am mocking getting phone numbers from Contacts Provider
        String[] exampleData = {"(979) 267-8509"}; 
        String[] examleProjection = new String[] { ContactsContract.CommonDataKinds.Phone.NUMBER};
        MatrixCursor matrixCursor = new MatrixCursor(examleProjection);
        matrixCursor.addRow(exampleData);

        //Step 2: Create a stub content provider and add the matrix cursor as the expected result of the query
        HashMapMockContentProvider mockProvider = new HashMapMockContentProvider();
        mockProvider.addQueryResult(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, matrixCursor);

        //Step 3: Create a mock resolver and add the content provider.
        MockContentResolver mockResolver = new MockContentResolver();
        mockResolver.addProvider(ContactsContract.AUTHORITY /*Needs to be the same as the authority of the provider you are mocking */, mockProvider);

        //Step 4: Add the mock resolver to the mock context
        ContextWithMockContentResolver mockContext = new ContextWithMockContentResolver(super.getContext());
        mockContext.setContentResolver(mockResolver);

        //Example Test 
        ExampleClassUnderTest underTest = new ExampleClassUnderTest();
        String result = underTest.getPhoneNumbers(mockContext);
        assertEquals("(979) 267-8509",result);
    }

    //Specialized Mock Content provider for step 2.  Uses a hashmap to return data dependent on the uri in the query
     public class HashMapMockContentProvider extends MockContentProvider{
         private HashMap<Uri, Cursor> expectedResults = new HashMap<Uri, Cursor>();
         public void addQueryResult(Uri uriIn, Cursor expectedResult){
             expectedResults.put(uriIn, expectedResult);
         }
         @Override
         public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder){
                return expectedResults.get(uri);
         } 
     }

     public class ContextWithMockContentResolver extends RenamingDelegatingContext {
            private ContentResolver contentResolver;
            public void setContentResolver(ContentResolver contentResolver){ this.contentResolver = contentResolver;}
            public ContextWithMockContentResolver(Context targetContext) { super(targetContext, "test");}
            @Override public ContentResolver getContentResolver() { return contentResolver; }
            @Override public Context getApplicationContext(){ return this; } //Added in-case my class called getApplicationContext() 
     }

     //An example class under test which queries the populated cursor to get the expected phone number 
     public class ExampleClassUnderTest{
         public  String getPhoneNumbers(Context context){//Query for  phone numbers from contacts
                String[] projection = new String[]{ ContactsContract.CommonDataKinds.Phone.NUMBER};
                Cursor cursor= context.getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, projection, null, null, null);
                cursor.moveToNext();
                return cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
         }
     }
}

如果不想传入上下文:

如果你想让被测类中的 getContext() 返回它而不是传递它，你应该能够像这样在你的 android 测试中覆盖 getContext()

@Override
 public Context getContext(){
    return new ContextWithMockContentResolver(super.getContext());   
 }