Commit 66155134 authored by Rob Pike's avatar Rob Pike

testing: make signalling safer for parallel tests

Each test gets a private signal channel.
Also fix a bug that prevented parallel tests from running.

R=r, r
CC=golang-dev
https://golang.org/cl/5505061
parent b5216e2e
......@@ -182,8 +182,8 @@ func (c *common) Fatalf(format string, args ...interface{}) {
// Parallel signals that this test is to be run in parallel with (and only with)
// other parallel tests in this CPU group.
func (t *T) Parallel() {
t.signal <- nil // Release main testing loop
<-t.startParallel // Wait for serial tests to finish
t.signal <- (*T)(nil) // Release main testing loop
<-t.startParallel // Wait for serial tests to finish
}
// An internal type but exported because it is cross-package; part of the implementation
......@@ -236,11 +236,14 @@ func RunTests(matchString func(pat, str string) (bool, error), tests []InternalT
fmt.Fprintln(os.Stderr, "testing: warning: no tests to run")
return
}
// TODO: each test should have its own channel, although that means
// keeping track of the channels when we're running parallel tests.
signal := make(chan interface{})
for _, procs := range cpuList {
runtime.GOMAXPROCS(procs)
// We build a new channel tree for each run of the loop.
// collector merges in one channel all the upstream signals from parallel tests.
// If all tests pump to the same channel, a bug can occur where a goroutine
// kicks off a test, fails, and still delivers a completion signal, which skews the
// counting.
var collector = make(chan interface{})
numParallel := 0
startParallel := make(chan bool)
......@@ -260,7 +263,7 @@ func RunTests(matchString func(pat, str string) (bool, error), tests []InternalT
}
t := &T{
common: common{
signal: signal,
signal: make(chan interface{}),
},
name: testName,
startParallel: startParallel,
......@@ -272,6 +275,9 @@ func RunTests(matchString func(pat, str string) (bool, error), tests []InternalT
go tRunner(t, &tests[i])
out := (<-t.signal).(*T)
if out == nil { // Parallel run.
go func() {
collector <- <-t.signal
}()
numParallel++
continue
}
......@@ -287,7 +293,7 @@ func RunTests(matchString func(pat, str string) (bool, error), tests []InternalT
numParallel--
continue
}
t := (<-signal).(*T)
t := (<-collector).(*T)
t.report()
ok = ok && !t.failed
running--
......
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