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Testing Sparse Resource Flag Detection in APK Processing in Apktool

This test suite validates the handling of sparse resources in Android APK files using the Apktool library. It ensures proper decoding and building of APKs with both sparse and non-sparse resource configurations, which is crucial for Android application reverse engineering and modification.

Test Coverage Overview

The test suite provides comprehensive coverage of sparse resource flag detection in APK files.

Tests both sparse and non-sparse APK configurations
Verifies correct resource flag detection during decoding
Validates APK rebuilding functionality
Covers edge cases with different resource configurations

Implementation Analysis

The implementation uses JUnit framework with a systematic approach to APK processing verification. The testing pattern follows a decode-then-build workflow, utilizing the ApkDecoder and ApkBuilder classes to process test APK files.

Framework features include:

BeforeClass setup for test resource preparation
Separate test cases for sparse and non-sparse scenarios
Configuration management through sConfig object

Technical Details

Testing infrastructure includes:

JUnit 4 testing framework
Custom BaseTest extension for common functionality
TestUtils for resource management
ExtFile wrapper for file operations
Logging system for test execution tracking

Best Practices Demonstrated

The test suite exemplifies several testing best practices in Java development.

Clear test method naming conventions
Proper test setup and resource management
Explicit assertions with meaningful messages
Isolated test cases for different scenarios
Effective use of inheritance for common test functionality

ibotpeaches/apktool

brut.apktool/apktool-lib/src/test/java/brut/androlib/decode/SparseFlagTest.java

            
/*
 *  Copyright (C) 2010 Ryszard Wiśniewski <[email protected]>
 *  Copyright (C) 2010 Connor Tumbleson <[email protected]>
 *
 *  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
 *
 *       https://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 brut.androlib.decode;

import brut.androlib.ApkBuilder;
import brut.androlib.ApkDecoder;
import brut.androlib.BaseTest;
import brut.androlib.TestUtils;
import brut.androlib.apk.ApkInfo;
import brut.common.BrutException;
import brut.directory.ExtFile;

import org.junit.*;
import static org.junit.Assert.*;

public class SparseFlagTest extends BaseTest {

    @BeforeClass
    public static void beforeClass() throws Exception {
        LOGGER.info("Unpacking sparse.apk && not-sparse.apk...");
        TestUtils.copyResourceDir(SparseFlagTest.class, "decode/sparse", sTmpDir);
    }

    @Test
    public void decodeWithExpectationOfSparseResources() throws BrutException {
        sConfig.setFrameworkTag("issue-3298");

        LOGGER.info("Decoding sparse.apk...");
        ExtFile testApk = new ExtFile(sTmpDir, "sparse.apk");
        ExtFile testDir = new ExtFile(testApk + ".out");
        ApkInfo apkInfo = new ApkDecoder(testApk, sConfig).decode(testDir);

        assertTrue("Expecting sparse resources", apkInfo.sparseResources);

        LOGGER.info("Building sparse.apk...");
        new ApkBuilder(testDir, sConfig).build(null);
    }

    @Test
    public void decodeWithExpectationOfNoSparseResources() throws BrutException {
        sConfig.setFrameworkTag("issue-3298");

        LOGGER.info("Decoding not-sparse.apk...");
        ExtFile testApk = new ExtFile(sTmpDir, "not-sparse.apk");
        ExtFile testDir = new ExtFile(testApk + ".out");
        ApkInfo apkInfo = new ApkDecoder(testApk, sConfig).decode(testDir);

        assertFalse("Expecting not-sparse resources", apkInfo.sparseResources);

        LOGGER.info("Building not-sparse.apk...");
        new ApkBuilder(testDir, sConfig).build(null);
    }
}