test: Add test emulators to Travis CI configuration

Author: gaurivn

.travis.yml

@@ -6,12 +6,16 @@ android:
     - tools
     - build-tools-28.0.3
     - android-28
+    - sys-img-x86-android-27
 before_install:
  - yes | ${ANDROID_HOME}/tools/bin/sdkmanager "platforms;android-28"
+ - emulator -avd test -no-audio -no-window &
+ - android-wait-for-emulator
 before_script:
  - chmod +x gradlew
  - chmod +x generate-apks.sh
 script:
  - ./gradlew build
+ - ./gradlew clean build connectedAndroidTest
 after_success:
  - ./generate-apks.sh