No call to expected at this point. Still 1 call(s) to expected error

In the integration test, i am using groovy mock feature to mock a service method like shown below:

def mock = new groovy.mock.interceptor.MockFor(PaymentService)

mock.demand.processPayment(){ a, b, c-> ['status': true, 'approved': true, 'tresponse':  new TransactionResponse(amount: total.toBigDecimal(), transactionId: "4234234555", saleId: Sale.last().id, responseCode: "1", responseReasonCode: "1", responseReasonText: "approved", authorizationCode: "asdasd", paymentMethod: "CC", transactionType: "auth_capture", cardCodeResponse: "P").save(flush: true)]}


mock.use{
    controller.paymentService = new PaymentService()

    populateReceiptParams(total)

    controller.receipt()

}

The payment controller method receipt() uses payment service method processPayment which communicates with authorize.net. So i have mocked out this method as shown above.

When the test is run, the error i am getting is as follows

junit.framework.AssertionFailedError: No call to 'getMergedSale' expected at this point. Still 1 call(s) to 'processPayment' expected.
    at PaymentController.cart(PaymentController.groovy:296)
    at PaymentController.receipt(PaymentController.groovy:1096)

So the thing is that inside receipt method there is another call to paymentservice being made

paymentService.getMergedSale([sessionAuth, userAuth])

So does this mean that the mocked method which is processPayment must be called first before getMergedSale? I appreciate any guide as to the reason for this error. Thanks!

So does this mean that the mocked method which is processPayment must be called first before getMergedSale?

Not necessarily, no. It does mean that you need to provide a mocked implementation of getMergedSale.