How do I check my override Model is working?

I wrote an override to vendormagentomodule-salesModelOrderPdfAbstractPdf.php

I did enable my override, I did run magento setup, di compile and flush the cache. Everything went smooth. But seems still using the old AbstractPdf.php. I don’t see anything from the log, what can I do about it?

Thank you

I create below

app/code/Company/ShipmentPdf/registration.php

app/code/Company/ShipmentPdf/etc/di.xml

app/code/ProjectA/ShipmentPdf/etc/module.xml

app/code/Company/ShipmentPdf/Model/Order/Pdf/AbstractPdf.php (changed namespace and I did edit some simple code for changing layout)

namespace ProjectAShipmentPdfModelOrderPdf;

app/code/Company/ProjectA/ShipmentPdf/Model/Order/Pdf/Config.php (changed namespace )

namespace ProjectAShipmentPdfModelOrderPdf;

Before, I was modify on the core and its work, then I roll it back and create above to override. I just only use this AbstractPdf for the packing list. Yes, I know it is Parent Class, Shouldn’t be rewrite by this way and will affect other child by using this class. But I know I just use this for the packing list only.