Override getAccounts to return an empty AccountSet in MockAccountManager. This used to throw an NPE instead since IAccountManagerService is set to NULL.
diff --git a/test-runner/android/test/IsolatedContext.java b/test-runner/android/test/IsolatedContext.java
index 4bd9528..5c66169 100644
--- a/test-runner/android/test/IsolatedContext.java
+++ b/test-runner/android/test/IsolatedContext.java
@@ -4,6 +4,7 @@
 
 import android.accounts.AccountManager;
 import android.accounts.OnAccountsUpdatedListener;
+import android.accounts.Account;
 import android.content.ContextWrapper;
 import android.content.ContentResolver;
 import android.content.Intent;
@@ -101,6 +102,10 @@
                 Handler handler, boolean updateImmediately) {
             // do nothing
         }
+
+        public Account[] getAccounts() {
+            return new Account[]{};
+        }
     }
     @Override
     public File getFilesDir() {