In this recipe, we will stub a method that returns a value so that it returns our desired result.
For this recipe, our system under test will be MeanTaxFactorCalculator, which calls TaxFactorFetcher twice to get a tax factor for the given person and then calculates a mean value for those two results as follows:
public class MeanTaxFactorCalculator {
private final TaxFactorFetcher taxFactorFetcher;
public MeanTaxFactorCalculator(TaxFactorFetcher taxFactorFetcher) {
this.taxFactorFetcher = taxFactorFetcher;
}
public double calculateMeanTaxFactorFor(Person person) {
double taxFactor = taxFactorFetcher.getTaxFactorFor(person);
double anotherTaxFactor = taxFactorFetcher.getTaxFactorFor(person);
return (taxFactor + anotherTaxFactor) / 2;
}
}