Fix: Support for snapshot tests on Intel and M1

[bstien]

Why?

As mentioned in the iOS meeting yesterday the snapshot tests would not run successfully on M1, since there's a small color difference between the architectures when rendering shadows and cornerRadius.

The issue is described here:
pointfreeco/swift-snapshot-testing#313
pointfreeco/swift-snapshot-testing#424

As we discussed there's an open PR that masks this issue by allowing pixels to have a slightly different value, which will work for us until we're all on M1 sometime™. Since it's not merged yet we will point to @pimms fork (thank you!) until it is or we figure out another solution.

subpixelThreshold will make sure that the color channel values (RGBA) of all pixels are within the threshold. I.e. the snapshot tests won't fail if the reference pixel is #000000FF and the produced pixel is #040404FF.

PNG issue

After setting this up yesterday some tests were still failing, and I noticed that there is a tiiiiiny difference in placement when it comes to rendering some PNG images.

Kapture.2022-02-10.at.11.59.04.mp4

I'm not sure of the reason and if this applies to all PNGs, or just those with different sizes (@1x, @2x, @3x), but I reached out to Sanjin and got an updated icon in PDF to use when we need a placeholder.

What?

• Point SnapshotTesting to https://github.com/pimms/swift-snapshot-testing
• Set subpixelThreshold to 5.
• Replace PNG image .noImage with an updated PDF.
• Retake snapshots for all views using this 👆

Version Change

Minor. No breaking changes.

UI Changes

Old icon	New icon

[pimms]

🙂