Do tests really use images from 'ReferenceOutput' folder?

Prerequisites

• I have written a descriptive issue title
• I have verified that I am running the latest version of ImageSharp
• I have verified if the problem exist in both DEBUG and RELEASE mode
• I have searched open and closed issues to ensure it has not already been reported

ImageSharp version

main branch

Other ImageSharp packages and versions

None

Environment (Operating system, version and so on)

Windows 10

.NET Framework version

net6

Description

I was writing tests for jpeg encoder PR and looked at the tests which compare saved images to reference images from 'ReferenceOutput' folder. Thing is, I don't see anything related to that folder in test code. Just to be sure I've deleted 'ReferenceOutput/PngEncoderTests' folder and all of png encoder tests still pass.

Most likely I've missed something but I just can't see any connections to this folder in test code.

Steps to Reproduce

Delete 'ReferenceOutput/PngEncoderTests' folder and launch png tests.

Images

No response

Start by running the PNG encoder tests after deleting ReferenceOutput/PngEncoderTests, then trace how those tests obtain their expected outputs. Done means establishing whether the folder is used and documenting or correcting the test setup so the tests behave as intended.