Injecting test doubles instead of beans using Spring's XML configuration

In the following recipe, we will replace an existing bean with a test double using Spring's XML configuration.

Getting ready

Let's assume that our system under test is the tax transferring system for a given person, as shown in the following code:

public class TaxTransferer {

    private final TaxService taxService;

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

    public boolean transferTaxFor(Person person) {
        if (person == null) {
            return false;
        }
        taxService.transferTaxFor(person);
        return true;
    }

}

As shown in the previous example, TaxService is a class that will perform a web service call. For readability purposes, we are simulating that we have such data exchanged as follows:

class TaxService {

    public void transferTaxFor(Person person) {
        System.out.printf("Calling external web service for person with name ...