Add a "DemoProvider" that always shows INFO...

                <action android:name="android.content.action.DOCUMENTS_PROVIDER" />

            </intent-filter>

       </provider>

       <!-- Provider that demostrates some features, like display of INFO and ERROR messages. -->

       <provider

            android:name="com.android.documentsui.DemoProvider"

            android:authorities="com.android.documentsui.demoprovider"

            android:exported="true"

            android:grantUriPermissions="true"

            android:permission="android.permission.MANAGE_DOCUMENTS"

            android:enabled="true">

            <intent-filter>

                <action android:name="android.content.action.DOCUMENTS_PROVIDER" />

            </intent-filter>

       </provider>

    </application>

    <instrumentation android:name="android.support.test.runner.AndroidJUnitRunner"

/*

 * Copyright (C) 2016 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.android.documentsui;

import android.database.Cursor;

import android.database.MatrixCursor;

import android.database.MatrixCursor.RowBuilder;

import android.os.Bundle;

import android.os.CancellationSignal;

import android.os.ParcelFileDescriptor;

import android.provider.DocumentsContract;

import android.provider.DocumentsContract.Document;

import android.provider.DocumentsContract.Root;

import android.provider.DocumentsProvider;

import java.io.FileNotFoundException;

/**

 * Provides data view that exercises some of the more esoteric functionality...like

 * display of INFO and ERROR messages.

 *

 * <p>Do not use this provider for automated testing.

 */

public class DemoProvider extends DocumentsProvider {

    private static final String ROOT_ID = "demo-root";

    private static final String[] DEFAULT_ROOT_PROJECTION = new String[] {

            Root.COLUMN_ROOT_ID,

            Root.COLUMN_FLAGS,

            Root.COLUMN_TITLE,

            Root.COLUMN_DOCUMENT_ID,

            Root.COLUMN_AVAILABLE_BYTES

    };

    private static final String[] DEFAULT_DOCUMENT_PROJECTION = new String[] {

            Document.COLUMN_DOCUMENT_ID,

            Document.COLUMN_MIME_TYPE,

            Document.COLUMN_DISPLAY_NAME,

            Document.COLUMN_LAST_MODIFIED,

            Document.COLUMN_FLAGS,

            Document.COLUMN_SIZE,

    };

    @Override

    public Cursor queryRoots(String[] projection) throws FileNotFoundException {

        MatrixCursor c = new MatrixCursor(

                projection != null ? projection : DEFAULT_ROOT_PROJECTION);

        final RowBuilder row = c.newRow();

        row.add(Root.COLUMN_ROOT_ID, ROOT_ID);

        row.add(Root.COLUMN_FLAGS, 0);

        row.add(Root.COLUMN_TITLE, "Demo Root");

        row.add(Root.COLUMN_DOCUMENT_ID, "root0");

        row.add(Root.COLUMN_AVAILABLE_BYTES, 1024 * 1024 * 100);

        return c;

    }

    @Override

    public Cursor queryDocument(String documentId, String[] projection)

            throws FileNotFoundException {

        MatrixCursor c = new MatrixCursor(

                projection != null ? projection : DEFAULT_DOCUMENT_PROJECTION);

            Bundle extras = new Bundle();

            c.setExtras(extras);

            extras.putString(

                    DocumentsContract.EXTRA_INFO,

                    "This provider is for feature demos only. Do not use from automated tests.");

        addFolder(c, documentId);

        return c;

    }

    @Override

    public Cursor queryChildDocuments(

            String parentDocumentId, String[] projection, String sortOrder)

            throws FileNotFoundException {

        MatrixCursor c = new MatrixCursor(

                projection != null ? projection : DEFAULT_DOCUMENT_PROJECTION);

        Bundle extras = new Bundle();

        c.setExtras(extras);

        switch (parentDocumentId) {

            case "aaa":

                extras.putString(

                        DocumentsContract.EXTRA_INFO,

                        "I'm a synthetic INFO. Don't judge me.");

                addFile(c, "zzz");

                break;

            case "bbb":

                extras.putString(

                        DocumentsContract.EXTRA_INFO,

                        "I'm a synthetic INFO. Don't judge me.");

                break;

            case "ccc":

                extras.putString(

                        DocumentsContract.EXTRA_INFO,

                        "INFO: I'm confused. I've show both ERROR and INFO.");

                extras.putString(

                        DocumentsContract.EXTRA_ERROR,

                        "ERROR: I'm confused. I've show both ERROR and INFO.");

                break;

            default:

                addFolder(c, "aaa");

                addFolder(c, "bbb");

                addFolder(c, "ccc");

                break;

        }

        return c;

    }

    private void addFolder(MatrixCursor c, String id) {

        final RowBuilder row = c.newRow();

        row.add(Document.COLUMN_DOCUMENT_ID, id);

        row.add(Document.COLUMN_DISPLAY_NAME, id);

        row.add(Document.COLUMN_SIZE, 0);

        row.add(Document.COLUMN_MIME_TYPE, DocumentsContract.Document.MIME_TYPE_DIR);

        row.add(Document.COLUMN_FLAGS, 0);

        row.add(Document.COLUMN_LAST_MODIFIED, System.currentTimeMillis());

    }

    private void addFile(MatrixCursor c, String id) {

        final RowBuilder row = c.newRow();

        row.add(Document.COLUMN_DOCUMENT_ID, id);

        row.add(Document.COLUMN_DISPLAY_NAME, id);

        row.add(Document.COLUMN_SIZE, 0);

        row.add(Document.COLUMN_MIME_TYPE, "text/plain");

        row.add(Document.COLUMN_FLAGS, 0);

        row.add(Document.COLUMN_LAST_MODIFIED, System.currentTimeMillis());

    }

    @Override

    public ParcelFileDescriptor openDocument(String documentId, String mode,

            CancellationSignal signal) throws FileNotFoundException {

        throw new UnsupportedOperationException("Nope!");

    }

    @Override

    public boolean onCreate() {

        return true;

    }

}