public void should_return_a_covariate_field_with_the_properties_set_as_expected()
 {
     _newCovariateField.ShouldNotBeNull();
     _newCovariateField.Covariate.ShouldBeEqualTo(_covariateField.Covariate);
     _newCovariateField.GroupingItems.ShouldOnlyContainInOrder(_covariateField.GroupingItems);
 }
 public void should_return_a_covariate_field()
 {
     _covariate.ShouldNotBeNull();
 }