package statistics import ( "math" "testing" "time" ) func TestBackoff(t *testing.T) { stats := NewStatistics(nil, 7) server := ServerStatistics{ statistics: &stats, serverName: "test.com", } // Start by checking that counting successes works. server.Success() if successes := server.SuccessCount(); successes != 1 { t.Fatalf("Expected success count 1, got %d", successes) } // Register a failure. server.Failure() t.Logf("Backoff counter: %d", server.backoffCount.Load()) // Now we're going to simulate backing off a few times to see // what happens. for i := uint32(1); i <= 10; i++ { // Register another failure for good measure. This should have no // side effects since a backoff is already in progress. If it does // then we'll fail. until, blacklisted := server.Failure() // Get the duration. _, blacklist := server.BackoffInfo() duration := time.Until(until) // Unset the backoff, or otherwise our next call will think that // there's a backoff in progress and return the same result. server.cancel() server.backoffStarted.Store(false) // Check if we should be blacklisted by now. if i >= stats.FailuresUntilBlacklist { if !blacklist { t.Fatalf("Backoff %d should have resulted in blacklist but didn't", i) } else if blacklist != blacklisted { t.Fatalf("BackoffInfo and Failure returned different blacklist values") } else { t.Logf("Backoff %d is blacklisted as expected", i) continue } } // Check if the duration is what we expect. t.Logf("Backoff %d is for %s", i, duration) roundingAllowance := 0.01 minDuration := time.Millisecond * time.Duration(math.Exp2(float64(i))*minJitterMultiplier*1000-roundingAllowance) maxDuration := time.Millisecond * time.Duration(math.Exp2(float64(i))*maxJitterMultiplier*1000+roundingAllowance) var inJitterRange bool if duration >= minDuration && duration <= maxDuration { inJitterRange = true } else { inJitterRange = false } if !blacklist && !inJitterRange { t.Fatalf("Backoff %d should have been between %s and %s but was %s", i, minDuration, maxDuration, duration) } } }