Program: 130818
Project: 130818
Buggy source:
@Test public void lineItems() throws Exception {
  withUpdateableType(client(),type -> {
    withPersistentChannel(client(),ChannelRole.INVENTORY_SUPPLY,channel -> {
      withProduct(client(),product -> {
        final int variantId=1;
        final String sku=sku(product);
        final ProductVariantImportDraft productVariantImportDraft=ProductVariantImportDraftBuilder.of(product.getId(),variantId,sku).build();
        final String value="String_Node_Str";
        final PriceDraft price=PriceDraft.of(EURO_1).withCustom(CustomFieldsDraft.ofTypeIdAndObjects(type.getId(),singletonMap(STRING_FIELD_NAME,value)));
        final LocalizedString name=randomSlug();
        final LineItemImportDraft lineItemImportDraft=LineItemImportDraftBuilder.of(productVariantImportDraft,2L,price,name).supplyChannel(channel).build();
        testOrderAspect(builder -> builder.lineItems(asList(lineItemImportDraft)),order -> {
          final LineItem lineItem=order.getLineItems().get(0);
          assertThat(lineItem.getProductId()).isEqualTo(product.getId());
          assertThat(lineItem.getVariant().getId()).isEqualTo(variantId);
          final ProductVariant masterVariant=product.getMasterData().getStaged().getMasterVariant();
          assertThat(lineItem.getVariant().getAttributes()).isEqualTo(masterVariant.getAttributes());
          assertThat(lineItem.getVariant().getImages()).isEqualTo(masterVariant.getImages());
          assertThat(lineItem.getVariant().getPrices()).isEqualTo(masterVariant.getPrices());
          assertThat(lineItem.getVariant().getSku()).contains(masterVariant.getSku());
          assertThat(lineItem.getQuantity()).isEqualTo(2);
          assertThat(lineItem.getName()).isEqualTo(name);
          assertThat(lineItem.getPrice().getCustom()).isNotNull();
        }
);
      }
);
    }
);
    return type;
  }
);
}

Fixed version (ground truth):
@Test public void lineItems() throws Exception {
  withUpdateableType(client(),type -> {
    withPersistentChannel(client(),ChannelRole.INVENTORY_SUPPLY,channel -> {
      withProduct(client(),product -> {
        final String value="String_Node_Str";
        final PriceDraft price=PriceDraft.of(EURO_1).withCustom(CustomFieldsDraft.ofTypeIdAndObjects(type.getId(),singletonMap(STRING_FIELD_NAME,value)));
        final String orderNumber=randomString();
        final int variantId=1;
        final String sku=sku(product);
        final ProductVariantImportDraft productVariantImportDraft=ProductVariantImportDraftBuilder.of(product.getId(),variantId,sku).prices(asList(price)).build();
        final LocalizedString name=randomSlug();
        final LineItemImportDraft lineItemImportDraft=LineItemImportDraftBuilder.of(productVariantImportDraft,2L,price,name).supplyChannel(channel).build();
        testOrderAspect(builder -> builder.lineItems(asList(lineItemImportDraft)).orderNumber(orderNumber),order -> {
          final LineItem lineItem=order.getLineItems().get(0);
          assertThat(lineItem.getProductId()).isEqualTo(product.getId());
          assertThat(lineItem.getVariant().getId()).isEqualTo(variantId);
          final ProductVariant masterVariant=product.getMasterData().getStaged().getMasterVariant();
          assertThat(lineItem.getVariant().getAttributes()).isEqualTo(masterVariant.getAttributes());
          assertThat(lineItem.getVariant().getImages()).isEqualTo(masterVariant.getImages());
          assertThat(lineItem.getVariant().getPrices()).isNotEmpty();
          assertThat(lineItem.getVariant().getSku()).contains(masterVariant.getSku());
          assertThat(lineItem.getQuantity()).isEqualTo(2);
          assertThat(lineItem.getName()).isEqualTo(name);
          assertThat(lineItem.getPrice().getCustom()).isNotNull();
        }
);
      }
);
    }
);
    return type;
  }
);
}