@Test
public void loadInterstitial_shouldPropagateJsonParamsInServerExtras() throws Exception {

    subject.loadInterstitial();
    expectedLocalExtras.put("Ad-Configuration", null);
    expectedServerExtras.put("key", "value");
    expectedServerExtras.put("a different key", "a different value");
    verify(interstitial).loadInterstitial(
            any(Context.class),
            eq(subject),
            eq(expectedLocalExtras),
            eq(expectedServerExtras)
    );
}