source: class CartValidatorTest {
  
      private final String cartRefNo;
      private final PaletteLabel cartLabel;
      private CartValidator validator;
  
      @Test
      public void someProductExpectedInOtherPocket() throws Exception {
  
target:         requiredProductsInCart("900901", "900902", "900903", "900904");
          RegisterNew command = givenCartRegistrationCommand("900902", "900901", "900903", "900904");
  
          ValidationResult result = validator.validate(command);
  
          Assertions.assertThat(result.getViolations())
                  .contains(
                          "refNo 900901 expected in pocket 1, but found in 2",
                          "refNo 900902 expected in pocket 2, but found in 1");
  
      }
  
  }