// Copyright 2013 The Go Authors.  All rights reserved.// Use of this source code is governed by a BSD-style// license that can be found in the LICENSE file. package debug import (	"runtime"	"testing"	"time") func TestReadGCStats(t *testing.T) {	defer SetGCPercent(SetGCPercent(-1)) 	var stats GCStats	var mstats runtime.MemStats	var min, max time.Duration 	// First ReadGCStats will allocate, second should not,	// especially if we follow up with an explicit garbage collection.	stats.PauseQuantiles = make([]time.Duration, 10)	ReadGCStats(&stats)	runtime.GC() 	// Assume these will return same data: no GC during ReadGCStats.	ReadGCStats(&stats)	runtime.ReadMemStats(&mstats) 	if stats.NumGC != int64(mstats.NumGC) {		t.Errorf("stats.NumGC = %d, but mstats.NumGC = %d", stats.NumGC, mstats.NumGC)	}	if stats.PauseTotal != time.Duration(mstats.PauseTotalNs) {		t.Errorf("stats.PauseTotal = %d, but mstats.PauseTotalNs = %d", stats.PauseTotal, mstats.PauseTotalNs)	}	if stats.LastGC.UnixNano() != int64(mstats.LastGC) {		t.Errorf("stats.LastGC.UnixNano = %d, but mstats.LastGC = %d", stats.LastGC.UnixNano(), mstats.LastGC)	}	n := int(mstats.NumGC)	if n > len(mstats.PauseNs) {		n = len(mstats.PauseNs)	}	if len(stats.Pause) != n {		t.Errorf("len(stats.Pause) = %d, want %d", len(stats.Pause), n)	} else {		off := (int(mstats.NumGC) + len(mstats.PauseNs) - 1) % len(mstats.PauseNs)		for i := 0; i < n; i++ {			dt := stats.Pause[i]			if dt != time.Duration(mstats.PauseNs[off]) {				t.Errorf("stats.Pause[%d] = %d, want %d", i, dt, mstats.PauseNs[off])			}			if max < dt {				max = dt			}			if min > dt || i == 0 {				min = dt			}			off = (off + len(mstats.PauseNs) - 1) % len(mstats.PauseNs)		}	} 	q := stats.PauseQuantiles	nq := len(q)	if q[0] != min || q[nq-1] != max {		t.Errorf("stats.PauseQuantiles = [%d, ..., %d], want [%d, ..., %d]", q[0], q[nq-1], min, max)	} 	for i := 0; i < nq-1; i++ {		if q[i] > q[i+1] {			t.Errorf("stats.PauseQuantiles[%d]=%d > stats.PauseQuantiles[%d]=%d", i, q[i], i+1, q[i+1])		}	} 	// compare memory stats with gc stats:	if len(stats.PauseEnd) != n {		t.Fatalf("len(stats.PauseEnd) = %d, want %d", len(stats.PauseEnd), n)	}	off := (int(mstats.NumGC) + len(mstats.PauseEnd) - 1) % len(mstats.PauseEnd)	for i := 0; i < n; i++ {		dt := stats.PauseEnd[i]		if dt.UnixNano() != int64(mstats.PauseEnd[off]) {			t.Errorf("stats.PauseEnd[%d] = %d, want %d", i, dt, mstats.PauseEnd[off])		}		off = (off + len(mstats.PauseEnd) - 1) % len(mstats.PauseEnd)	}} var big = make([]byte, 1<<20) func TestFreeOSMemory(t *testing.T) {	if runtime.GOARCH == "arm64" || runtime.GOARCH == "ppc64" || runtime.GOARCH == "ppc64le" || runtime.GOARCH == "mips64" || runtime.GOARCH == "mips64le" ||		runtime.GOOS == "nacl" {		t.Skip("issue 9993; scavenger temporarily disabled on systems with physical pages larger than logical pages")	}	var ms1, ms2 runtime.MemStats 	if big == nil {		t.Skip("test is not reliable when run multiple times")	}	big = nil	runtime.GC()	runtime.ReadMemStats(&ms1)	FreeOSMemory()	runtime.ReadMemStats(&ms2)	if ms1.HeapReleased >= ms2.HeapReleased {		t.Errorf("released before=%d; released after=%d; did not go up", ms1.HeapReleased, ms2.HeapReleased)	}} func TestSetGCPercent(t *testing.T) {	// Test that the variable is being set and returned correctly.	// Assume the percentage itself is implemented fine during GC,	// which is harder to test.	old := SetGCPercent(123)	new := SetGCPercent(old)	if new != 123 {		t.Errorf("SetGCPercent(123); SetGCPercent(x) = %d, want 123", new)	}}