Testing that it doesn’t have text doesn’t help if the text was a bitmap in the first place. Normally the use case is that you still want to distribute it as a

Testing that it doesn’t have text doesn’t help if the text was a bitmap in the first place. Normally the use case is that you still want to distribute it as a PDF, usually consisting of many pages, and without loss of quality, so the printing/scanning/screenshotting option may not be very practical. No, the real solution is to use an editor that allows you to remove text (and/or cut out bitmaps), before you add black rectangles for clarity.