tree b829d1b4d502b594c5dc7107df4bc16ace110173
parent 64d9ab524de3f07e96cda88e3ef296291ee6dfc7
author Mikio Hara <mikioh.mikioh@gmail.com> 1430434152 +0900
committer Mikio Hara <mikioh.mikioh@gmail.com> 1430898397 +0000

net: deflake listener tests

This change makes TestDualStack{TCP,UDP}Listener work more properly by
attempting to book an available service port before testing.

Also simplifies error messages in tests.

Fixes #5001.

Change-Id: If13b0d0039878c9bd32061a0440664e4fa7abaf7
Reviewed-on: https://go-review.googlesource.com/9661
Reviewed-by: Ian Lance Taylor <iant@golang.org>