Verify tests for DC

[armfazh]

Tests for DCs fail when running isolated, but they pass when invoked as a batch (i.e. go test -v -run=.)

What did you do?

$ cd src/crypto/tls
$ ../../../bin/go test -v -run=DC

What did you expect to see?

=== RUN   TestDCHandshakeServerAuth
--- PASS: TestDCHandshakeServerAuth (0.14s)
=== RUN   TestDCHandshakeClientAuth
--- PASS: TestDCHandshakeClientAuth (0.14s)
=== RUN   TestDCHandshakeClientAndServerAuth
--- PASS: TestDCHandshakeClientAndServerAuth (0.03s)

What did you see instead?

    delegated_credentials_test.go:592: test #1 dcCounter:1, (tls13: DC server and client support) fails: x509: certificate signed by unknown authority
    delegated_credentials_test.go:598: test #1 (tls13: DC server and client support) usedDC = false; expected true
    delegated_credentials_test.go:592: test #1 dcCounter:2, (tls13: DC server and client support) fails: x509: certificate signed by unknown authority
    delegated_credentials_test.go:598: test #1 (tls13: DC server and client support) usedDC = false; expected true
    delegated_credentials_test.go:592: test #1 dcCounter:3, (tls13: DC server and client support) fails: x509: certificate signed by unknown authority
    delegated_credentials_test.go:598: test #1 (tls13: DC server and client support) usedDC = false; expected true

[claucece]

Yes, I see. I'm not really sure why is only flagged in this case of testing but I can take a look at this next week.

The problem is that we are providing a mock of a certificate (without the correct root and chain and all), as it is only for testing.

We can provide that whole chain, though it might be too much for testing. Or just set the c.config.InsecureSkipVerify to true, as it is often on testing, which will invalidate the check (as it fails on verifyServerCertificate).

[claucece]

I added a PR @armfazh ;) Let me know your thoughts.

[claucece]

Merged now.