RuntimeService runtimeService = activitiRule.getRuntimeService();
TaskService taskService = activitiRule.getTaskService();
HistoryService historyService = activitiRule.getHistoryService();
// Prepare fake camel behavior
CamelBehaviourStub camelBehaviour = new CamelBehaviourStub();
Mocks.register("camel", camelBehaviour);
// Start process instance
ProcessInstance processInstance = runtimeService.startProcessInstanceByKey("open-account");