Testing pdf generation with jest

I want to test generation of pdf on my client. For generating i use pdfMake library. And to check if the text inside a pdf is correct i want to parse it but i cant come up with a method to do it.

I know that pdfMake makes blob with pdf data and then i can open it in a tab in browser but how can i check generated data? Seems like i cant access pdf after it opens in window object, so i tried to parse blob or buffer after creating a document. But all pdf-parsing libs seem to work only with existing file on disk and not on blobs or buffers. Are there any solutions? Or the only thing i can do check inside document definition? It would be grate if i also would be able to access coordinates of the document if this possible.