@Test
public void multipleProductMissingInCart() throws Exception {

    requiredProductsInCart("900901", "900902", "900903", "900904");
    RegisterNew command = givenCartRegistrationCommand("900901", "900903");
    ValidationResult result = validator.validate(command);
    Assertions.assertThat(result.getViolations())
            .contains(
                    "refNo 900904 expected in pocket 4, but not found",
                    "refNo 900902 expected in pocket 2, but not found");
}