### Question:
StripeApiHandler { @VisibleForTesting static String getRetrieveCustomerUrl(@NonNull String customerId) { return String.format(Locale.ENGLISH, "%s/%s", getCustomersUrl(), customerId); }    }### Answer:
@Test public void testGetRetrieveCustomerUrl() { String customerId = "cus_123abc"; String customerRequestUrl = StripeApiHandler.getRetrieveCustomerUrl(customerId); assertEquals("https: }