net: external network tests flaky

[alberts]

This is the first of a few bugs to track test flakiness and get it fixed.

Even on a reasonably reliable 10 Mbps DSL internet connection, tests that touch the
external network fail from time to time.

Example:

--- FAIL: TestDialGoogleIPv4 (10.03 seconds)
dialgoogle_test.go:66: lookup www.google.com: lookup www.google.com: no such host

This leads to a constant stream of failures that have to be triaged (a few per day).

These tests need to be skipped based on an environment variable (or something) so that
no matter if they're run through "go test", run.bash, etc., they can easily be
skipped.

Everyone else running go test net and make.bash are constantly testing these.

[minux]

Comment 1:

i prefer a GO_NO_EXTERNAL_NETWORK or similar named environment variables to control
these tests.
another case is in go.crypto/ssh/test where it tries to connect encrypted.google.com and
causing builder failures
(http://build.golang.org/log/b8a386d137101f8da0a77c5688f7e6ece8400257)

[alberts]

Comment 2:

Sounds good to me. If there's consensus, I'll prepare a CL.

[mikioh]

Comment 3:

Doesn't testExternal work well? I think tests with flags -short=true or -external=false
does work well on any environment. How did you run?

[alberts]

Comment 4:

How do I turn testExternal off when running with run.bash?
Using testExternal is also tricky when you just want to do go test std.
I'm trying to run all the Go tests in the same way that everyone runs them, but also in
extra ways that expose more subtle race conditions/bugs.

[mikioh]

Comment 5:

Ah, I see. That's the reason why prefix is "testing".

[alberts]

Comment 6:

go.crypto/ssh again:
http://build.golang.org/log/60b807a82d52d5fed20cf9459346a41878cb3600
http://build.golang.org/log/dee0ab25201464a6e1851b0c6c9e7695c3df8393

[rsc]

Comment 7:

Labels changed: added priority-later, go1.2, removed priority-triage.

Status changed to Accepted.

[rsc]

Comment 8:

Labels changed: added testing.

[rsc]

Comment 9:

Labels changed: added go1.2maybe, removed go1.2.

[rsc]

Comment 10:

Labels changed: added go1.3, removed go1.2maybe.

[rsc]

Comment 11:

Labels changed: added release-go1.3.

[rsc]

Comment 12:

Labels changed: removed go1.3.

[rsc]

Comment 13:

Labels changed: added repo-main.

[mikioh]

Comment 14:

Labels changed: added release-go1.4, removed release-go1.3.

[hanwen]

Comment 15:

Fixed. The external network test has been removed from go.crypto/ssh now.

[rsc]

Comment 16:

Labels changed: added release-none, removed release-go1.4.