Change GetGooglePlayServices to use reflection to avoid build errors in some tests.

Author: jonsimantov

testing/test_framework/src/android/java/com/google/firebase/example/TestHelper.java

@@ -16,7 +16,8 @@
 
 import android.content.Context;
 import android.os.Build;
-import com.google.android.gms.common.GoogleApiAvailability;
+import java.lang.Class;
+import java.lang.reflect.Method;
 
 /**
  * A simple class with test helper methods.
@@ -31,6 +32,22 @@ public static boolean isRunningOnEmulator() {
         || Build.DEVICE.contains("vbox86p") || Build.HARDWARE.contains("vbox86");
   }
   public static int getGooglePlayServicesVersion(Context context) {
-    return GoogleApiAvailability.getInstance().getApkVersion(context);
+      // Use reflection to invoke GoogleApiAvailability.getInstance().getApkVersion(context).
+      // This avoids needing Google Play services to be present (and returns 0 if it's not)..
+
+      // GoogleApiAvailability
+      Class<?> googleApiAvailabilityClass = Class.forName("com.google.android.gms.common.GoogleApiAvailability");
+      if (googleApiAvailabilityClass == null) {
+	  return 0;
+      }
+      // .getInstance()
+      Method getInstanceMethod = googleApiAvailabilityClass.getDeclaredMethod("getInstance");
+      Object instance = getInstanceMethod.invoke(null);
+
+      // .getApkVersion(context)
+      Method getApkVersionMethod = googleApiAvailabilityClass.getMethod("getApkVersion", new Class[]{context.class});
+      Object apkVersionObject = getInstanceMethod.invoke(instance, context);
+
+      int apkVersion = apkVersionObject.intValue;
   }
 }

testing/test_framework/src/firebase_test_framework.h

@@ -354,7 +354,8 @@ class FirebaseTest : public testing::Test {
   // on a real device (or on desktop).
   static bool IsRunningOnEmulator();
 
-  // Return Google Play services version on Android, 0 elsewhere.
+  // If on Android and Google Play services is available, returns the
+  // Google Play services version. Otherwise, returns 0.
   static int GetGooglePlayServicesVersion();
 
   // Returns true if the future completed as expected, fails the test and