prober: fix test flake

This was tested by running 10000 test iterations and observing no flakes
after this change was made.

Change-Id: Ib036fd03a3a17800132c53c838cc32bfe2961306
Signed-off-by: Andrew Dunham <andrew@tailscale.com>
pull/6168/head
Andrew Dunham 2 years ago committed by Andrew Dunham
parent 988c1f0ac7
commit 06b55ab50f

@ -97,7 +97,7 @@ func TestProberTimingSpread(t *testing.T) {
} }
} }
p.Run("test-spread-probe", probeInterval, nil, func(context.Context) error { probe := p.Run("test-spread-probe", probeInterval, nil, func(context.Context) error {
invoked <- struct{}{} invoked <- struct{}{}
return nil return nil
}) })
@ -110,6 +110,36 @@ func TestProberTimingSpread(t *testing.T) {
clk.Advance(halfProbeInterval) clk.Advance(halfProbeInterval)
called() called()
notCalled() notCalled()
// We need to wait until the main (non-initial) ticker in Probe.loop is
// waiting, or we could race and advance the test clock between when
// the initial delay ticker completes and before the ticker for the
// main loop is created. In this race, we'd first advance the test
// clock, then the ticker would be registered, and the test would fail
// because that ticker would never be fired.
err := tstest.WaitFor(convergenceTimeout, func() error {
clk.Lock()
defer clk.Unlock()
for _, tick := range clk.tickers {
tick.Lock()
stopped, interval := tick.stopped, tick.interval
tick.Unlock()
if stopped {
continue
}
// Test for the main loop, not the initialDelay
if interval == probe.interval {
return nil
}
}
return fmt.Errorf("no ticker with interval %d found", probe.interval)
})
if err != nil {
t.Fatal(err)
}
clk.Advance(quarterProbeInterval) clk.Advance(quarterProbeInterval)
notCalled() notCalled()
clk.Advance(probeInterval) clk.Advance(probeInterval)

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