Introduce instrumentation tests

app/test/src/main/AndroidManifest.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8"?>
+<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>
+
+    <instrumentation
+        android:name="androidx.test.runner.AndroidJUnitRunner"
+        android:targetPackage="com.topjohnwu.magisk"
+        android:label="Tests for Magisk" />
+
+</manifest>