Verifying the method invocation count with times()

In this recipe, we will verify whether a method on a mock was executed for exactly the given number of times.

Getting ready

For this recipe, our system under test will be TaxUpdater, which calls TaxService (let's assume that it is a web-service client) to update the mean tax factor for two people. Unfortunately, this system is old and can accept a single call at a time. For simplicity, the calculateMeanTaxFactor() method, shown in the following code, returns a fixed value but in reality, there could be some complex logic:

public class TaxUpdater {

    static final double MEAN_TAX_FACTOR = 10.5;

    private final TaxService taxService;

    public TaxUpdater(TaxService taxService) {
        this.taxService = taxService;
    }

    public void updateTaxFactorFor(Person brother, Person sister) {
        taxService.updateMeanTaxFactor(brother,calculateMeanTaxFactor());
        taxService.updateMeanTaxFactor(sister,calculateMeanTaxFactor...