From 32faa4ced6c5f8e02c098d102ef170b8dbf20b62 Mon Sep 17 00:00:00 2001
From: topjohnwu <topjohnwu@gmail.com>
Date: Wed, 25 Dec 2024 20:17:57 -0800
Subject: [PATCH] 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             |  9 +++++++--
 app/test/proguard-rules.pro           | 13 +++++++++++++
 app/test/src/main/AndroidManifest.xml |  2 --
 build.py                              | 16 +++++++++++++---
 buildSrc/src/main/java/Setup.kt       |  4 +++-
 scripts/test_common.sh                |  2 +-
 6 files changed, 37 insertions(+), 9 deletions(-)
 create mode 100644 app/test/proguard-rules.pro

diff --git a/app/test/build.gradle.kts b/app/test/build.gradle.kts
index 1ed6b421b..92ae38c9f 100644
--- a/app/test/build.gradle.kts
+++ b/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)
diff --git a/app/test/proguard-rules.pro b/app/test/proguard-rules.pro
new file mode 100644
index 000000000..e4388a243
--- /dev/null
+++ b/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 *
diff --git a/app/test/src/main/AndroidManifest.xml b/app/test/src/main/AndroidManifest.xml
index 46e3bba77..fa7d5c44d 100644
--- a/app/test/src/main/AndroidManifest.xml
+++ b/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>
diff --git a/build.py b/build.py
index 99de53552..f562de03c 100755
--- a/build.py
+++ b/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
 
 
 ################
diff --git a/buildSrc/src/main/java/Setup.kt b/buildSrc/src/main/java/Setup.kt
index d9c13a6eb..773439dbe 100644
--- a/buildSrc/src/main/java/Setup.kt
+++ b/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 {
diff --git a/scripts/test_common.sh b/scripts/test_common.sh
index 452eb9441..a9eb4e8e0 100644
--- a/scripts/test_common.sh
+++ b/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'