Junit5+Multidex环境下Espresso测试Gradle CLI执行失败问题

I've dug into your issue where your JUnit 5-powered Espresso tests run fine in Android Studio 4 but throw errors when executed via the Gradle CLI with ./gradlew app:connectedDebugAndroidTest. The two core errors you're seeing—NoSuchMethodError for ConcurrentHashMap.newKeySet() and the missing junit-platform-runner—stem from Dex splitting behavior introduced with AGP 4.0, combined with Java 8 desugaring and MultiDex configuration gaps. Here's how to fix it step by step:

1. Force Critical JUnit 5 & Desugared Classes Into Main Dex #

When AGP splits your test APK into multiple Dex files, critical initialization classes (like the JUnit 5 runner and desugared ConcurrentHashMap) might end up in non-primary Dex files, which aren't loaded early enough during instrumentation startup. To fix this:

First, add a dexOptions block to your app/build.gradle to specify a main Dex list:

android {
    // ... existing config
    dexOptions {
        preDexLibraries = false
        additionalParameters = [
                '--main-dex-list', file('main-dex-list.txt').absolutePath
        ]
    }
}

Then create a main-dex-list.txt file in your app module directory, and add these fully qualified class names:

de/mannodermaus/junit5/AndroidJUnit5Builder.class
org/junit/platform/runner/JUnitPlatform.class
org/junit/platform/commons/logging/LoggerFactory.class
j$/util/concurrent/ConcurrentHashMap.class

This ensures these classes are packaged into the primary Dex file, so they're available when the instrumentation runner starts up.

2. Tweak MultiDex & Test Runner Configuration #

Your CustomEspressoTestRunner already calls MultiDex.install, but we need to make sure it runs first, and that the test APK has MultiDex explicitly enabled:

Update your defaultConfig in app/build.gradle:

defaultConfig {
    testInstrumentationRunner "com.bonial.framework.utils.CustomEspressoTestRunner"
    testInstrumentationRunnerArgument "runnerBuilder", "de.mannodermaus.junit5.AndroidJUnit5Builder"
    multiDexEnabled true // Enable MultiDex for test APK
    // ... other config
}

And adjust your CustomEspressoTestRunner to prioritize MultiDex installation above all other initialization logic:

@Suppress("unused")
class CustomEspressoTestRunner : AndroidJUnitRunner() {
    override fun onCreate(arguments: Bundle?) {
        // Install MultiDex FIRST to ensure all Dex files are loaded early
        MultiDex.install(getTargetContext())
        // Then apply StrictMode and call super.onCreate
        StrictMode.setThreadPolicy(StrictMode.ThreadPolicy.Builder().permitAll().build())
        super.onCreate(arguments)
    }

    @Throws(InstantiationException::class, IllegalAccessException::class, ClassNotFoundException::class)
    override fun newApplication(cl: ClassLoader?, className: String?, context: Context?): Application? {
        return super.newApplication(cl, EspressoTestApplication::class.java.name, context)
    }
}

3. Update Java 8 Desugaring Dependencies #

AGP 4.0 has known quirks with desugaring libraries. Ensure you're using a recent desugaring dependency in your dependencies block:

dependencies {
    // ... existing dependencies
    coreLibraryDesugaring "com.android.tools:desugar_jdk_libs:1.1.5"
}

This ensures all desugared JDK classes (like the missing ConcurrentHashMap method) are properly included in your test APK.

4. Clean & Rebuild to Eliminate Cached Dex Files #

Old cached Dex files can cause unexpected behavior. Run these commands to start fresh:

./gradlew clean app:assembleDebugAndroidTest app:connectedDebugAndroidTest

Why This Works: #

• By forcing critical classes into the main Dex, we avoid the "class not found" errors that happen when instrumentation tries to load classes from non-primary Dex files too early.
• Prioritizing MultiDex installation ensures all Dex splits are initialized before any test logic runs.
• Updating the desugaring library fixes gaps in AGP 4.0's handling of Java 8 APIs in test environments.

内容的提问来源于stack exchange，提问作者Auras