### Question:
StripeApiHandler { @VisibleForTesting static String getRetrieveSourceApiUrl(@NonNull String sourceId) { return String.format(Locale.ENGLISH, "%s/%s", getSourcesUrl(), sourceId); }    }### Answer:
@Test public void testGetRetrieveSourceUrl() { String sourceUrlWithId = StripeApiHandler.getRetrieveSourceApiUrl("abc123"); assertEquals("https: }