Writing JUnit tests for Spring Validator implementation

I'm using Spring Validator implementations to validate my object and I would like to know how do you write a unit test for a validator like this one:

public class CustomerValidator implements Validator {

private final Validator addressValidator;

public CustomerValidator(Validator addressValidator) {
    if (addressValidator == null) {
        throw new IllegalArgumentException(
          "The supplied [Validator] is required and must not be null.");
    }
    if (!addressValidator.supports(Address.class)) {
        throw new IllegalArgumentException(
          "The supplied [Validator] must support the validation of [Address] instances.");
    }
    this.addressValidator = addressValidator;
}

/**
* This Validator validates Customer instances, and any subclasses of Customer too
*/
public boolean supports(Class clazz) {
    return Customer.class.isAssignableFrom(clazz);
}

public void validate(Object target, Errors errors) {
    ValidationUtils.rejectIfEmptyOrWhitespace(errors, "firstName", "field.required");
    ValidationUtils.rejectIfEmptyOrWhitespace(errors, "surname", "field.required");
    Customer customer = (Customer) target;
    try {
        errors.pushNestedPath("address");
        ValidationUtils.invokeValidator(this.addressValidator, customer.getAddress(), errors);
    } finally {
        errors.popNestedPath();
    }
}
}

How can I unit test CustomerValidator without calling the real implementation of the AddressValidator (by mocking it)? I've haven't seen any example like that...

In other words, what I really want to do here is to mock the AddressValidator which is called and instanciated inside the CustomerValidator... is there a way to mock this AddressValidator?

Or maybe I'm looking at it the wrong way? Maybe what I need to do is to mock the call to ValidationUtils.invokeValida