Try setting up an emulator in CI

.github/workflows/ci.yml

@@ -46,4 +46,64 @@ jobs:
           asset_name: android-frida-interception-script-${{ github.ref }}.js
           file: ./build/android-frida-interception-script.js
           tag: ${{ github.ref }}
-          repo_token: ${{ secrets.GITHUB_TOKEN }}
+          repo_token: ${{ secrets.GITHUB_TOKEN }}
+
+  test-android:
+    name: Test on Android emulator
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        api-level: [30]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+
+      - name: Install Frida CLI
+        run: |
+          pip install --user frida-tools
+          echo "$HOME/.local/bin" >> $GITHUB_PATH
+
+      # Apparently significantly improves emulator performance:
+      - name: Enable KVM
+        run: |
+          echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' | sudo tee /etc/udev/rules.d/99-kvm4all.rules
+          sudo udevadm control --reload-rules
+          sudo udevadm trigger --name-match=kvm
+
+      # Cache the emulator AVD:
+      - name: AVD cache
+        uses: actions/cache@v4
+        id: avd-cache
+        with:
+          path: |
+            ~/.android/avd/*
+            ~/.android/adb*
+          key: avd-${{ matrix.api-level }}
+
+      - name: Create AVD and cache snapshot
+        if: steps.avd-cache.outputs.cache-hit != 'true'
+        uses: reactivecircus/android-emulator-runner@v2
+        with:
+          api-level: ${{ matrix.api-level }}
+          target: google_apis
+          force-avd-creation: false
+          emulator-options: -no-window -gpu swiftshader_indirect -noaudio -no-boot-anim -camera-back none
+          script: |
+            echo "Generated AVD snapshot for caching."
+
+      - name: Run tests
+        uses: reactivecircus/android-emulator-runner@v2
+        with:
+          api-level: ${{ matrix.api-level }}
+          target: google_apis
+          force-avd-creation: false
+          emulator-options: -no-snapshot-save -no-window -gpu swiftshader_indirect -noaudio -no-boot-anim -camera-back none
+          script: |
+            adb devices
+            bash test/android/setup-emulator.sh
+            echo "Emulator ready to test"
+            adb shell pgrep -f frida-server

test/android/setup-emulator.sh

@@ -0,0 +1,47 @@
+#!/bin/bash
+set -e
+
+# Assumes: Android emulator/device is available via ADB and Frida CLI is installed on computer
+# Wait for device, install APK, and set up Frida server (all idempotent)
+
+# Wait for emulator/device to be available
+adb wait-for-device
+adb shell 'while [[ -z $(getprop sys.boot_completed) ]]; do sleep 1; done;'
+echo "Emulator/device booted."
+
+# Download and install APK if not already installed
+APK_PATH="/tmp/pinning-demo.apk"
+APK_URL="https://github.com/httptoolkit/android-ssl-pinning-demo/releases/download/v1.4.1/pinning-demo.apk"
+PACKAGE="tech.httptoolkit.pinning_demo"
+if ! adb shell pm list packages | grep -q "$PACKAGE"; then
+  wget -q $APK_URL -O $APK_PATH
+  adb install -r $APK_PATH
+  echo "APK installed."
+else
+  echo "APK already installed."
+fi
+
+# Set up Frida server
+FRIDA_VERSION=$(frida --version)
+FRIDA_SERVER_URL="https://github.com/frida/frida/releases/download/${FRIDA_VERSION}/frida-server-${FRIDA_VERSION}-android-x86.xz"
+FRIDA_SERVER_LOCAL="/tmp/frida-server"
+FRIDA_SERVER_REMOTE="/data/local/tmp/frida-server"
+
+if ! adb shell pgrep -f frida-server > /dev/null; then
+  if [ ! -f $FRIDA_SERVER_LOCAL ]; then
+    wget -q $FRIDA_SERVER_URL -O /tmp/frida-server.xz
+    unxz -f /tmp/frida-server.xz
+    chmod +x $FRIDA_SERVER_LOCAL
+  fi
+  adb root || true
+  sleep 1
+  adb push $FRIDA_SERVER_LOCAL $FRIDA_SERVER_REMOTE
+  echo 'Pushed'
+  adb shell "chmod 755 $FRIDA_SERVER_REMOTE"
+  echo 'chmoded'
+  adb shell "ls -l $FRIDA_SERVER_REMOTE"
+  adb shell "$FRIDA_SERVER_REMOTE" &
+  echo "Frida server started on device."
+else
+  echo "Frida server already running."
+fi