Lazy vars shared validators

spec.js

sharedExampleFor('Range validator', function(fieldName, min, max) {
  it('rejects values greater than "max" value', function() {
    $subject[fieldName] = max() + 1;
    expect($subject.hasErrorOn(fieldName)).to.be.true;
  });
  
  it('rejects values less than "min" value', function() {
    $subject[fieldName] = min() - 1;
    expect($subject.hasErrorOn(fieldName)).to.be.true;
  });
});