Where is docker conformance-test?

[abitrolly]

@rhatdan wrote in #5733 (comment)

One issue is docker does not support --exclude in conformance-test right now.

Where is this conformance-test? Is it some independent tests suite for tools? I am asking, because COPY --exclude added in #5733 doesn't behave the same way as in Docker - #6726

/cc @nalind @flouthoc @giuseppe

[nalind]

The conformance tests go through the client API, and live in the tests/conformance directory.

[abitrolly]

So it is not something maintained by industry to keep compatibility across tools. Everybody hunts compatibility bugs and writes the same tests themselves.