fix(ci): test release build in emulator test

Previously the debug build was tested, meaning proguard issues
would slip through and cause unexpected crashes

This adds a test keystore creation step so release signing works,
then switches to release mode gradle targets and toggles on release
build testing

.github/workflows/tests_emulator.yml

@@ -20,6 +20,13 @@ jobs:
     timeout-minutes: 75
     env:
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+      TEST_RELEASE_BUILD: true
+      # could be better, '/home/runner' should be '~/' but neither that nor '$HOME' worked
+      STOREFILEDIR: /home/runner/src
+      STOREFILE: android-keystore
+      STOREPASS: testpass
+      KEYPASS: testpass
+      KEYALIAS: nrkeystorealias
     strategy:
       fail-fast: false
       matrix:
@@ -33,6 +40,15 @@ jobs:
         # This is useful for benchmarking, do 0, 1, 2, etc (up to 256 max job-per-matrix limit) for averages
         iteration: [0]
     steps:
+      - name: Test Credential Prep
+        run: |
+          echo "KSTOREPWD=$STOREPASS" >> $GITHUB_ENV
+          echo "KEYPWD=$KEYPASS" >> $GITHUB_ENV
+          mkdir $STOREFILEDIR
+          cd $STOREFILEDIR
+          echo y | keytool -genkeypair -dname "cn=AnkiDroid, ou=ankidroid, o=AnkiDroid, c=US" -alias $KEYALIAS -keypass $KEYPASS -keystore "$STOREFILE" -storepass $STOREPASS -keyalg RSA -validity 20000
+        shell: bash
+
       - uses: actions/checkout@v4
         with:
           fetch-depth: 50
@@ -80,7 +96,7 @@ jobs:
           timeout_minutes: 15
           retry_wait_seconds: 60
           max_attempts: 3
-          command: ./gradlew packagePlayDebug packagePlayDebugAndroidTest --daemon
+          command: ./gradlew packagePlayRelease packagePlayReleaseAndroidTest --daemon
 
       - name: AVD Boot and Snapshot Creation
         # Only generate a snapshot for saving if we are on main branch with a cache miss