os/signal: TestTerminalSignal is failing on multiple builders

[mundaym]

builder	issue	example
linux-amd64-clang	race between command and ^Z? (only seen once)	link
linux-arm	race between command and ^Z?	link
linux-s390x-ibm	test timeout	link
android-arm-wiko-fever	compilation: could not determine kind of name for C.posix_openpt	link
dragonfly-amd64	context timeout	link
solaris-amd64-oraclerel	no ^Z?	link
solaris-amd64-smartosbuildlet	compilation: #error "Compiler or options invalid; UNIX 03 and POSIX.1-2001 applications require the use of c99"	link

I think the linux-arm and linux-amd64-clang failures are due to the ^Z being issued before the command has started. I experience this locally on linux/s390x and if I increase the duration of the intervening time.Sleep call then the test passes. I suspect we need a more robust mechanism to check the command has started than time.Sleep.

I'm not sure why the linux/s390x builder is timing out. I'll investigate.

[gopherbot]

Change https://golang.org/cl/79395 mentions this issue: os/signal: make TestTerminalSignal more reliable

[gopherbot]

Change https://golang.org/cl/79399 mentions this issue: os/signal: don't run TestTerminalSignal on Android

[mundaym]

I think all the builders are now 'ok' again, thanks Ian.