### Question:
PersistenceManagerImpl implements PersistenceManager { @Override public void setSourceToken(String sourceToken) { sharedPreferences.edit().putString(Key.SOURCE_TOKEN, sourceToken).apply(); } @VisibleForTesting  PersistenceManagerImpl(Context context); @Override void setSessionId(String sessionId); @Nullable @Override String getSessionId(); @Override void setSourceToken(String sourceToken); @Nullable @Override String getSourceToken(); @Override void clear(); @Override boolean checkedDeferredDeepLink(); @Override void updateCheckDeferredDeepLink(boolean checkedDeferredDeepLink);  }### Answer:
@Test public void setSourceToken_persistToSharedPrefs() { persistenceManager.setSourceToken("valid_source_token"); verify(editor).putString(PersistenceManagerImpl.Key.SOURCE_TOKEN, "valid_source_token"); verify(editor).apply(); }