// 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 runtime_test
import (
"fmt"
"math"
"reflect"
"runtime"
"sort"
"strings"
"sync"
"testing"
)
// negative zero is a good test because:
// 1) 0 and -0 are equal, yet have distinct representations.
// 2) 0 is represented as all zeros, -0 isn't.
// I'm not sure the language spec actually requires this behavior,
// but it's what the current map implementation does.
func TestNegativeZero(t *testing.T) {
m := make(map[float64]bool, 0)
m[+0.0] = true
m[math.Copysign(0.0, -1.0)] = true // should overwrite +0 entry
if len(m) != 1 {
t.Error("length wrong")
}
for k := range m {
if math.Copysign(1.0, k) > 0 {
t.Error("wrong sign")
}
}
m = make(map[float64]bool, 0)
m[math.Copysign(0.0, -1.0)] = true
m[+0.0] = true // should overwrite -0.0 entry
if len(m) != 1 {
t.Error("length wrong")
}
for k := range m {
if math.Copysign(1.0, k) < 0 {
t.Error("wrong sign")
}
}
}
// nan is a good test because nan != nan, and nan has
// a randomized hash value.
func TestNan(t *testing.T) {
m := make(map[float64]int, 0)
nan := math.NaN()
m[nan] = 1
m[nan] = 2
m[nan] = 4
if len(m) != 3 {
t.Error("length wrong")
}
s := 0
for k, v := range m {
if k == k {
t.Error("nan disappeared")
}
if (v & (v - 1)) != 0 {
t.Error("value wrong")
}
s |= v
}
if s != 7 {
t.Error("values wrong")
}
}
// Maps aren't actually copied on assignment.
func TestAlias(t *testing.T) {
m := make(map[int]int, 0)
m[0] = 5
n := m
n[0] = 6
if m[0] != 6 {
t.Error("alias didn't work")
}
}
func TestGrowWithNaN(t *testing.T) {
m := make(map[float64]int, 4)
nan := math.NaN()
m[nan] = 1
m[nan] = 2
m[nan] = 4
cnt := 0
s := 0
growflag := true
for k, v := range m {
if growflag {
// force a hashtable resize
for i := 0; i < 100; i++ {
m[float64(i)] = i
}
growflag = false
}
if k != k {
cnt++
s |= v
}
}
if cnt != 3 {
t.Error("NaN keys lost during grow")
}
if s != 7 {
t.Error("NaN values lost during grow")
}
}
type FloatInt struct {
x float64
y int
}
func TestGrowWithNegativeZero(t *testing.T) {
negzero := math.Copysign(0.0, -1.0)
m := make(map[FloatInt]int, 4)
m[FloatInt{0.0, 0}] = 1
m[FloatInt{0.0, 1}] = 2
m[FloatInt{0.0, 2}] = 4
m[FloatInt{0.0, 3}] = 8
growflag := true
s := 0
cnt := 0
negcnt := 0
// The first iteration should return the +0 key.
// The subsequent iterations should return the -0 key.
// I'm not really sure this is required by the spec,
// but it makes sense.
// TODO: are we allowed to get the first entry returned again???
for k, v := range m {
if v == 0 {
continue
} // ignore entries added to grow table
cnt++
if math.Copysign(1.0, k.x) < 0 {
if v&16 == 0 {
t.Error("key/value not updated together 1")
}
negcnt++
s |= v & 15
} else {
if v&16 == 16 {
t.Error("key/value not updated together 2", k, v)
}
s |= v
}
if growflag {
// force a hashtable resize
for i := 0; i < 100; i++ {
m[FloatInt{3.0, i}] = 0
}
// then change all the entries
// to negative zero
m[FloatInt{negzero, 0}] = 1 | 16
m[FloatInt{negzero, 1}] = 2 | 16
m[FloatInt{negzero, 2}] = 4 | 16
m[FloatInt{negzero, 3}] = 8 | 16
growflag = false
}
}
if s != 15 {
t.Error("entry missing", s)
}
if cnt != 4 {
t.Error("wrong number of entries returned by iterator", cnt)
}
if negcnt != 3 {
t.Error("update to negzero missed by iteration", negcnt)
}
}
func TestIterGrowAndDelete(t *testing.T) {
m := make(map[int]int, 4)
for i := 0; i < 100; i++ {
m[i] = i
}
growflag := true
for k := range m {
if growflag {
// grow the table
for i := 100; i < 1000; i++ {
m[i] = i
}
// delete all odd keys
for i := 1; i < 1000; i += 2 {
delete(m, i)
}
growflag = false
} else {
if k&1 == 1 {
t.Error("odd value returned")
}
}
}
}
// make sure old bucket arrays don't get GCd while
// an iterator is still using them.
func TestIterGrowWithGC(t *testing.T) {
m := make(map[int]int, 4)
for i := 0; i < 16; i++ {
m[i] = i
}
growflag := true
bitmask := 0
for k := range m {
if k < 16 {
bitmask |= 1 << uint(k)
}
if growflag {
// grow the table
for i := 100; i < 1000; i++ {
m[i] = i
}
// trigger a gc
runtime.GC()
growflag = false
}
}
if bitmask != 1<<16-1 {
t.Error("missing key", bitmask)
}
}
func testConcurrentReadsAfterGrowth(t *testing.T, useReflect bool) {
if runtime.GOMAXPROCS(-1) == 1 {
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(16))
}
numLoop := 10
numGrowStep := 250
numReader := 16
if testing.Short() {
numLoop, numGrowStep = 2, 500
}
for i := 0; i < numLoop; i++ {
m := make(map[int]int, 0)
for gs := 0; gs < numGrowStep; gs++ {
m[gs] = gs
var wg sync.WaitGroup
wg.Add(numReader * 2)
for nr := 0; nr < numReader; nr++ {
go func() {
defer wg.Done()
for range m {
}
}()
go func() {
defer wg.Done()
for key := 0; key < gs; key++ {
_ = m[key]
}
}()
if useReflect {
wg.Add(1)
go func() {
defer wg.Done()
mv := reflect.ValueOf(m)
keys := mv.MapKeys()
for _, k := range keys {
mv.MapIndex(k)
}
}()
}
}
wg.Wait()
}
}
}
func TestConcurrentReadsAfterGrowth(t *testing.T) {
testConcurrentReadsAfterGrowth(t, false)
}
func TestConcurrentReadsAfterGrowthReflect(t *testing.T) {
testConcurrentReadsAfterGrowth(t, true)
}
func TestBigItems(t *testing.T) {
var key [256]string
for i := 0; i < 256; i++ {
key[i] = "foo"
}
m := make(map[[256]string][256]string, 4)
for i := 0; i < 100; i++ {
key[37] = fmt.Sprintf("string%02d", i)
m[key] = key
}
var keys [100]string
var values [100]string
i := 0
for k, v := range m {
keys[i] = k[37]
values[i] = v[37]
i++
}
sort.Strings(keys[:])
sort.Strings(values[:])
for i := 0; i < 100; i++ {
if keys[i] != fmt.Sprintf("string%02d", i) {
t.Errorf("#%d: missing key: %v", i, keys[i])
}
if values[i] != fmt.Sprintf("string%02d", i) {
t.Errorf("#%d: missing value: %v", i, values[i])
}
}
}
type empty struct {
}
func TestEmptyKeyAndValue(t *testing.T) {
a := make(map[int]empty, 4)
b := make(map[empty]int, 4)
c := make(map[empty]empty, 4)
a[0] = empty{}
b[empty{}] = 0
b[empty{}] = 1
c[empty{}] = empty{}
if len(a) != 1 {
t.Errorf("empty value insert problem")
}
if b[empty{}] != 1 {
t.Errorf("empty key returned wrong value")
}
}
// Tests a map with a single bucket, with same-lengthed short keys
// ("quick keys") as well as long keys.
func TestSingleBucketMapStringKeys_DupLen(t *testing.T) {
testMapLookups(t, map[string]string{
"x": "x1val",
"xx": "x2val",
"foo": "fooval",
"bar": "barval", // same key length as "foo"
"xxxx": "x4val",
strings.Repeat("x", 128): "longval1",
strings.Repeat("y", 128): "longval2",
})
}
// Tests a map with a single bucket, with all keys having different lengths.
func TestSingleBucketMapStringKeys_NoDupLen(t *testing.T) {
testMapLookups(t, map[string]string{
"x": "x1val",
"xx": "x2val",
"foo": "fooval",
"xxxx": "x4val",
"xxxxx": "x5val",
"xxxxxx": "x6val",
strings.Repeat("x", 128): "longval",
})
}
func testMapLookups(t *testing.T, m map[string]string) {
for k, v := range m {
if m[k] != v {
t.Fatalf("m[%q] = %q; want %q", k, m[k], v)
}
}
}
// Tests whether the iterator returns the right elements when
// started in the middle of a grow, when the keys are NaNs.
func TestMapNanGrowIterator(t *testing.T) {
m := make(map[float64]int)
nan := math.NaN()
const nBuckets = 16
// To fill nBuckets buckets takes LOAD * nBuckets keys.
nKeys := int(nBuckets * *runtime.HashLoad)
// Get map to full point with nan keys.
for i := 0; i < nKeys; i++ {
m[nan] = i
}
// Trigger grow
m[1.0] = 1
delete(m, 1.0)
// Run iterator
found := make(map[int]struct{})
for _, v := range m {
if v != -1 {
if _, repeat := found[v]; repeat {
t.Fatalf("repeat of value %d", v)
}
found[v] = struct{}{}
}
if len(found) == nKeys/2 {
// Halfway through iteration, finish grow.
for i := 0; i < nBuckets; i++ {
delete(m, 1.0)
}
}
}
if len(found) != nKeys {
t.Fatalf("missing value")
}
}
func TestMapIterOrder(t *testing.T) {
for _, n := range [...]int{3, 7, 9, 15} {
for i := 0; i < 1000; i++ {
// Make m be {0: true, 1: true, ..., n-1: true}.
m := make(map[int]bool)
for i := 0; i < n; i++ {
m[i] = true
}
// Check that iterating over the map produces at least two different orderings.
ord := func() []int {
var s []int
for key := range m {
s = append(s, key)
}
return s
}
first := ord()
ok := false
for try := 0; try < 100; try++ {
if !reflect.DeepEqual(first, ord()) {
ok = true
break
}
}
if !ok {
t.Errorf("Map with n=%d elements had consistent iteration order: %v", n, first)
break
}
}
}
}
// Issue 8410
func TestMapSparseIterOrder(t *testing.T) {
// Run several rounds to increase the probability
// of failure. One is not enough.
NextRound:
for round := 0; round < 10; round++ {
m := make(map[int]bool)
// Add 1000 items, remove 980.
for i := 0; i < 1000; i++ {
m[i] = true
}
for i := 20; i < 1000; i++ {
delete(m, i)
}
var first []int
for i := range m {
first = append(first, i)
}
// 800 chances to get a different iteration order.
// See bug 8736 for why we need so many tries.
for n := 0; n < 800; n++ {
idx := 0
for i := range m {
if i != first[idx] {
// iteration order changed.
continue NextRound
}
idx++
}
}
t.Fatalf("constant iteration order on round %d: %v", round, first)
}
}
func TestMapStringBytesLookup(t *testing.T) {
// Use large string keys to avoid small-allocation coalescing,
// which can cause AllocsPerRun to report lower counts than it should.
m := map[string]int{
"1000000000000000000000000000000000000000000000000": 1,
"2000000000000000000000000000000000000000000000000": 2,
}
buf := []byte("1000000000000000000000000000000000000000000000000")
if x := m[string(buf)]; x != 1 {
t.Errorf(`m[string([]byte("1"))] = %d, want 1`, x)
}
buf[0] = '2'
if x := m[string(buf)]; x != 2 {
t.Errorf(`m[string([]byte("2"))] = %d, want 2`, x)
}
var x int
n := testing.AllocsPerRun(100, func() {
x += m[string(buf)]
})
if n != 0 {
t.Errorf("AllocsPerRun for m[string(buf)] = %v, want 0", n)
}
x = 0
n = testing.AllocsPerRun(100, func() {
y, ok := m[string(buf)]
if !ok {
panic("!ok")
}
x += y
})
if n != 0 {
t.Errorf("AllocsPerRun for x,ok = m[string(buf)] = %v, want 0", n)
}
}
func TestMapLargeKeyNoPointer(t *testing.T) {
const (
I = 1000
N = 64
)
type T [N]int
m := make(map[T]int)
for i := 0; i < I; i++ {
var v T
for j := 0; j < N; j++ {
v[j] = i + j
}
m[v] = i
}
runtime.GC()
for i := 0; i < I; i++ {
var v T
for j := 0; j < N; j++ {
v[j] = i + j
}
if m[v] != i {
t.Fatalf("corrupted map: want %+v, got %+v", i, m[v])
}
}
}
func TestMapLargeValNoPointer(t *testing.T) {
const (
I = 1000
N = 64
)
type T [N]int
m := make(map[int]T)
for i := 0; i < I; i++ {
var v T
for j := 0; j < N; j++ {
v[j] = i + j
}
m[i] = v
}
runtime.GC()
for i := 0; i < I; i++ {
var v T
for j := 0; j < N; j++ {
v[j] = i + j
}
v1 := m[i]
for j := 0; j < N; j++ {
if v1[j] != v[j] {
t.Fatalf("corrupted map: want %+v, got %+v", v, v1)
}
}
}
}
func benchmarkMapPop(b *testing.B, n int) {
m := map[int]int{}
for i := 0; i < b.N; i++ {
for j := 0; j < n; j++ {
m[j] = j
}
for j := 0; j < n; j++ {
// Use iterator to pop an element.
// We want this to be fast, see issue 8412.
for k := range m {
delete(m, k)
break
}
}
}
}
func BenchmarkMapPop100(b *testing.B) { benchmarkMapPop(b, 100) }
func BenchmarkMapPop1000(b *testing.B) { benchmarkMapPop(b, 1000) }
func BenchmarkMapPop10000(b *testing.B) { benchmarkMapPop(b, 10000) }
func TestNonEscapingMap(t *testing.T) {
n := testing.AllocsPerRun(1000, func() {
m := make(map[int]int)
m[0] = 0
})
if n != 0 {
t.Fatalf("want 0 allocs, got %v", n)
}
}