Redesign test APK architecture

The test APK and the main APK share the same process and classloader,
and in the non-hidden case, the test APK's classes take precedence over
the ones in the main APK. This causes issues because the test APK and
main APK share some dependencies, but don't always use the same
version. This is especially problematic for the Kotlin stdlib and
AndroidX dependencies.

The solution here is to rely on R8's obfuscation feature and repackage
all potentially conflicting classes into a separate package in the test
APK. To ensure that the test classes are always using the same classes
as the main APK, we have to directly implement all tests inside the main
APK, making the test APK purely a "test runner with test dependencies".

As a result, the test APK can only be used when built in release mode,
because R8 no longer allow class obfuscation to be enabled when building
for debug versions.

app/test/build.gradle.kts

@@ -10,14 +10,19 @@ android {
         applicationId = "com.topjohnwu.magisk.test"
         versionCode = 1
         versionName = "1.0"
+        proguardFile("proguard-rules.pro")
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = true
+        }
     }
 }
 
 setupAppCommon()
 
 dependencies {
-    compileOnly(project(":app:core"))
-
     implementation(libs.test.runner)
     implementation(libs.test.rules)
     implementation(libs.test.junit)

app/test/proguard-rules.pro

@@ -0,0 +1,13 @@
+# Keep all test dependencies
+-keep class org.junit.** { *; }
+-keep class androidx.test.** { *; }
+
+# Make sure the classloader constructor is kept
+-keepclassmembers class com.topjohnwu.magisk.test.TestClassLoader { <init>(); }
+
+# Repackage dependencies
+-repackageclasses 'deps'
+-allowaccessmodification
+
+# Keep attributes for stacktrace
+-keepattributes *

app/test/src/main/AndroidManifest.xml

@@ -2,8 +2,6 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools">
 
-    <uses-permission tools:node="removeAll" />
-
     <application tools:node="replace">
         <uses-library android:name="android.test.runner" />
     </application>

build.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 import argparse
+import copy
 import glob
 import lzma
 import multiprocessing
@@ -455,9 +456,18 @@ def build_stub():
 
 
 def build_test():
-    header("* Building the test app")
-    apk = build_apk(":app:test")
-    header(f"Output: {apk}")
+    global args
+    args_bak = copy.copy(args)
+    # Test APK has to be built as release to prevent classname clash
+    args.release = True
+    try:
+        header("* Building the test app")
+        source = build_apk(":app:test")
+        target = source.parent / "test.apk"
+        mv(source, target)
+        header(f"Output: {target}")
+    finally:
+        args = args_bak
 
 
 ################

buildSrc/src/main/java/Setup.kt

@@ -17,7 +17,6 @@ import org.gradle.api.Action
 import org.gradle.api.DefaultTask
 import org.gradle.api.JavaVersion
 import org.gradle.api.Project
-import org.gradle.api.Task
 import org.gradle.api.file.DirectoryProperty
 import org.gradle.api.provider.Property
 import org.gradle.api.tasks.Copy
@@ -300,6 +299,9 @@ fun Project.setupAppCommon() {
 
         defaultConfig {
             targetSdk = 35
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt")
+            )
         }
 
         buildTypes {

scripts/test_common.sh

@@ -56,7 +56,7 @@ run_setup() {
   adb install -r -g out/app-${variant}.apk
 
   # Install the test app
-  adb install -r -g out/test-${variant}.apk
+  adb install -r -g out/test.apk
 
   # Run setup through the test app
   am_instrument 'Environment#setupMagisk'