### Question:
HeartbeatCustomDSInfo extends HeartbeatInfo { public void contributeToHttpCall(HeartbeatCall call) { call.addParameter("customDSClass[]", getServiceClass() == null ? "" : getServiceClass()); call.addParameter("customDSCount[]", String.valueOf(getCount())); }  String getServiceClass(); void setServiceClass(String serviceClass); void contributeToHttpCall(HeartbeatCall call); String getKey();  }### Answer:
@Test void contributeToHttpCall_serviceClassIsNull_customDSClassAndCountParamIsContributed() { objectUnderTest.contributeToHttpCall(heartbeatCall); verify(heartbeatCall).addParameter(CUSTOM_DS_CLASS_KEY, ""); verify(heartbeatCall).addParameter(CUSTOM_DS_COUNT_KEY, "0"); }