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go/container/intsets/sparse_test.go
Radu Berinde 1807494da8 x/tools/container/intsets: add LowerBound
Fixes golang/go#21310.

Change-Id: Id3f23a66b9889a5087c1f83e7d672d14c41a59e3
Reviewed-on: https://go-review.googlesource.com/53432
Reviewed-by: Alan Donovan <adonovan@google.com>
2017-08-21 16:11:21 +00:00

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// Copyright 2014 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 intsets_test
import (
"fmt"
"log"
"math/rand"
"sort"
"strings"
"testing"
"golang.org/x/tools/container/intsets"
)
func TestBasics(t *testing.T) {
var s intsets.Sparse
if len := s.Len(); len != 0 {
t.Errorf("Len({}): got %d, want 0", len)
}
if s := s.String(); s != "{}" {
t.Errorf("String({}): got %q, want \"{}\"", s)
}
if s.Has(3) {
t.Errorf("Has(3): got true, want false")
}
if err := s.Check(); err != nil {
t.Error(err)
}
if !s.Insert(3) {
t.Errorf("Insert(3): got false, want true")
}
if max := s.Max(); max != 3 {
t.Errorf("Max: got %d, want 3", max)
}
if !s.Insert(435) {
t.Errorf("Insert(435): got false, want true")
}
if s := s.String(); s != "{3 435}" {
t.Errorf("String({3 435}): got %q, want \"{3 435}\"", s)
}
if max := s.Max(); max != 435 {
t.Errorf("Max: got %d, want 435", max)
}
if len := s.Len(); len != 2 {
t.Errorf("Len: got %d, want 2", len)
}
if !s.Remove(435) {
t.Errorf("Remove(435): got false, want true")
}
if s := s.String(); s != "{3}" {
t.Errorf("String({3}): got %q, want \"{3}\"", s)
}
}
// Insert, Len, IsEmpty, Hash, Clear, AppendTo.
func TestMoreBasics(t *testing.T) {
set := new(intsets.Sparse)
set.Insert(456)
set.Insert(123)
set.Insert(789)
if set.Len() != 3 {
t.Errorf("%s.Len: got %d, want 3", set, set.Len())
}
if set.IsEmpty() {
t.Errorf("%s.IsEmpty: got true", set)
}
if !set.Has(123) {
t.Errorf("%s.Has(123): got false", set)
}
if set.Has(1234) {
t.Errorf("%s.Has(1234): got true", set)
}
got := set.AppendTo([]int{-1})
if want := []int{-1, 123, 456, 789}; fmt.Sprint(got) != fmt.Sprint(want) {
t.Errorf("%s.AppendTo: got %v, want %v", set, got, want)
}
set.Clear()
if set.Len() != 0 {
t.Errorf("Clear: got %d, want 0", set.Len())
}
if !set.IsEmpty() {
t.Errorf("IsEmpty: got false")
}
if set.Has(123) {
t.Errorf("%s.Has: got false", set)
}
}
func TestTakeMin(t *testing.T) {
var set intsets.Sparse
set.Insert(456)
set.Insert(123)
set.Insert(789)
set.Insert(-123)
var got int
for i, want := range []int{-123, 123, 456, 789} {
if !set.TakeMin(&got) || got != want {
t.Errorf("TakeMin #%d: got %d, want %d", i, got, want)
}
}
if set.TakeMin(&got) {
t.Errorf("%s.TakeMin returned true", &set)
}
if err := set.Check(); err != nil {
t.Fatalf("check: %s: %#v", err, &set)
}
}
func TestMinAndMax(t *testing.T) {
values := []int{0, 456, 123, 789, -123} // elt 0 => empty set
wantMax := []int{intsets.MinInt, 456, 456, 789, 789}
wantMin := []int{intsets.MaxInt, 456, 123, 123, -123}
var set intsets.Sparse
for i, x := range values {
if i != 0 {
set.Insert(x)
}
if got, want := set.Min(), wantMin[i]; got != want {
t.Errorf("Min #%d: got %d, want %d", i, got, want)
}
if got, want := set.Max(), wantMax[i]; got != want {
t.Errorf("Max #%d: got %d, want %d", i, got, want)
}
}
set.Insert(intsets.MinInt)
if got, want := set.Min(), intsets.MinInt; got != want {
t.Errorf("Min: got %d, want %d", got, want)
}
set.Insert(intsets.MaxInt)
if got, want := set.Max(), intsets.MaxInt; got != want {
t.Errorf("Max: got %d, want %d", got, want)
}
}
func TestEquals(t *testing.T) {
var setX intsets.Sparse
setX.Insert(456)
setX.Insert(123)
setX.Insert(789)
if !setX.Equals(&setX) {
t.Errorf("Equals(%s, %s): got false", &setX, &setX)
}
var setY intsets.Sparse
setY.Insert(789)
setY.Insert(456)
setY.Insert(123)
if !setX.Equals(&setY) {
t.Errorf("Equals(%s, %s): got false", &setX, &setY)
}
setY.Insert(1)
if setX.Equals(&setY) {
t.Errorf("Equals(%s, %s): got true", &setX, &setY)
}
var empty intsets.Sparse
if setX.Equals(&empty) {
t.Errorf("Equals(%s, %s): got true", &setX, &empty)
}
// Edge case: some block (with offset=0) appears in X but not Y.
setY.Remove(123)
if setX.Equals(&setY) {
t.Errorf("Equals(%s, %s): got true", &setX, &setY)
}
}
// A pset is a parallel implementation of a set using both an intsets.Sparse
// and a built-in hash map.
type pset struct {
hash map[int]bool
bits intsets.Sparse
}
func makePset() *pset {
return &pset{hash: make(map[int]bool)}
}
func (set *pset) add(n int) {
prev := len(set.hash)
set.hash[n] = true
grewA := len(set.hash) > prev
grewB := set.bits.Insert(n)
if grewA != grewB {
panic(fmt.Sprintf("add(%d): grewA=%t grewB=%t", n, grewA, grewB))
}
}
func (set *pset) remove(n int) {
prev := len(set.hash)
delete(set.hash, n)
shrankA := len(set.hash) < prev
shrankB := set.bits.Remove(n)
if shrankA != shrankB {
panic(fmt.Sprintf("remove(%d): shrankA=%t shrankB=%t", n, shrankA, shrankB))
}
}
func (set *pset) check(t *testing.T, msg string) {
var eltsA []int
for elt := range set.hash {
eltsA = append(eltsA, int(elt))
}
sort.Ints(eltsA)
eltsB := set.bits.AppendTo(nil)
if a, b := fmt.Sprint(eltsA), fmt.Sprint(eltsB); a != b {
t.Errorf("check(%s): hash=%s bits=%s (%s)", msg, a, b, &set.bits)
}
if err := set.bits.Check(); err != nil {
t.Fatalf("Check(%s): %s: %#v", msg, err, &set.bits)
}
}
// randomPset returns a parallel set of random size and elements.
func randomPset(prng *rand.Rand, maxSize int) *pset {
set := makePset()
size := int(prng.Int()) % maxSize
for i := 0; i < size; i++ {
// TODO(adonovan): benchmark how performance varies
// with this sparsity parameter.
n := int(prng.Int()) % 10000
set.add(n)
}
return set
}
// TestRandomMutations performs the same random adds/removes on two
// set implementations and ensures that they compute the same result.
func TestRandomMutations(t *testing.T) {
const debug = false
set := makePset()
prng := rand.New(rand.NewSource(0))
for i := 0; i < 10000; i++ {
n := int(prng.Int())%2000 - 1000
if i%2 == 0 {
if debug {
log.Printf("add %d", n)
}
set.add(n)
} else {
if debug {
log.Printf("remove %d", n)
}
set.remove(n)
}
if debug {
set.check(t, "post mutation")
}
}
set.check(t, "final")
if debug {
log.Print(&set.bits)
}
}
func TestLowerBound(t *testing.T) {
// Use random sets of sizes from 0 to about 4000.
prng := rand.New(rand.NewSource(0))
for i := uint(0); i < 12; i++ {
x := randomPset(prng, 1<<i)
for j := 0; j < 10000; j++ {
found := intsets.MaxInt
for e := range x.hash {
if e >= j && e < found {
found = e
}
}
if res := x.bits.LowerBound(j); res != found {
t.Errorf("%s: LowerBound(%d)=%d, expected %d", &x.bits, j, res, found)
}
}
}
}
// TestSetOperations exercises classic set operations: ∩ , , \.
func TestSetOperations(t *testing.T) {
prng := rand.New(rand.NewSource(0))
// Use random sets of sizes from 0 to about 4000.
// For each operator, we test variations such as
// Z.op(X, Y), Z.op(X, Z) and Z.op(Z, Y) to exercise
// the degenerate cases of each method implementation.
for i := uint(0); i < 12; i++ {
X := randomPset(prng, 1<<i)
Y := randomPset(prng, 1<<i)
// TODO(adonovan): minimise dependencies between stanzas below.
// Copy(X)
C := makePset()
C.bits.Copy(&Y.bits) // no effect on result
C.bits.Copy(&X.bits)
C.hash = X.hash
C.check(t, "C.Copy(X)")
C.bits.Copy(&C.bits)
C.check(t, "C.Copy(C)")
// U.Union(X, Y)
U := makePset()
U.bits.Union(&X.bits, &Y.bits)
for n := range X.hash {
U.hash[n] = true
}
for n := range Y.hash {
U.hash[n] = true
}
U.check(t, "U.Union(X, Y)")
// U.Union(X, X)
U.bits.Union(&X.bits, &X.bits)
U.hash = X.hash
U.check(t, "U.Union(X, X)")
// U.Union(U, Y)
U = makePset()
U.bits.Copy(&X.bits)
U.bits.Union(&U.bits, &Y.bits)
for n := range X.hash {
U.hash[n] = true
}
for n := range Y.hash {
U.hash[n] = true
}
U.check(t, "U.Union(U, Y)")
// U.Union(X, U)
U.bits.Copy(&Y.bits)
U.bits.Union(&X.bits, &U.bits)
U.check(t, "U.Union(X, U)")
// U.UnionWith(U)
U.bits.UnionWith(&U.bits)
U.check(t, "U.UnionWith(U)")
// I.Intersection(X, Y)
I := makePset()
I.bits.Intersection(&X.bits, &Y.bits)
for n := range X.hash {
if Y.hash[n] {
I.hash[n] = true
}
}
I.check(t, "I.Intersection(X, Y)")
// I.Intersection(X, X)
I.bits.Intersection(&X.bits, &X.bits)
I.hash = X.hash
I.check(t, "I.Intersection(X, X)")
// I.Intersection(I, X)
I.bits.Intersection(&I.bits, &X.bits)
I.check(t, "I.Intersection(I, X)")
// I.Intersection(X, I)
I.bits.Intersection(&X.bits, &I.bits)
I.check(t, "I.Intersection(X, I)")
// I.Intersection(I, I)
I.bits.Intersection(&I.bits, &I.bits)
I.check(t, "I.Intersection(I, I)")
// D.Difference(X, Y)
D := makePset()
D.bits.Difference(&X.bits, &Y.bits)
for n := range X.hash {
if !Y.hash[n] {
D.hash[n] = true
}
}
D.check(t, "D.Difference(X, Y)")
// D.Difference(D, Y)
D.bits.Copy(&X.bits)
D.bits.Difference(&D.bits, &Y.bits)
D.check(t, "D.Difference(D, Y)")
// D.Difference(Y, D)
D.bits.Copy(&X.bits)
D.bits.Difference(&Y.bits, &D.bits)
D.hash = make(map[int]bool)
for n := range Y.hash {
if !X.hash[n] {
D.hash[n] = true
}
}
D.check(t, "D.Difference(Y, D)")
// D.Difference(X, X)
D.bits.Difference(&X.bits, &X.bits)
D.hash = nil
D.check(t, "D.Difference(X, X)")
// D.DifferenceWith(D)
D.bits.Copy(&X.bits)
D.bits.DifferenceWith(&D.bits)
D.check(t, "D.DifferenceWith(D)")
// SD.SymmetricDifference(X, Y)
SD := makePset()
SD.bits.SymmetricDifference(&X.bits, &Y.bits)
for n := range X.hash {
if !Y.hash[n] {
SD.hash[n] = true
}
}
for n := range Y.hash {
if !X.hash[n] {
SD.hash[n] = true
}
}
SD.check(t, "SD.SymmetricDifference(X, Y)")
// X.SymmetricDifferenceWith(Y)
SD.bits.Copy(&X.bits)
SD.bits.SymmetricDifferenceWith(&Y.bits)
SD.check(t, "X.SymmetricDifference(Y)")
// Y.SymmetricDifferenceWith(X)
SD.bits.Copy(&Y.bits)
SD.bits.SymmetricDifferenceWith(&X.bits)
SD.check(t, "Y.SymmetricDifference(X)")
// SD.SymmetricDifference(X, X)
SD.bits.SymmetricDifference(&X.bits, &X.bits)
SD.hash = nil
SD.check(t, "SD.SymmetricDifference(X, X)")
// SD.SymmetricDifference(X, Copy(X))
X2 := makePset()
X2.bits.Copy(&X.bits)
SD.bits.SymmetricDifference(&X.bits, &X2.bits)
SD.check(t, "SD.SymmetricDifference(X, Copy(X))")
// Copy(X).SymmetricDifferenceWith(X)
SD.bits.Copy(&X.bits)
SD.bits.SymmetricDifferenceWith(&X.bits)
SD.check(t, "Copy(X).SymmetricDifferenceWith(X)")
}
}
func TestIntersectionWith(t *testing.T) {
// Edge cases: the pairs (1,1), (1000,2000), (8000,4000)
// exercise the <, >, == cases in IntersectionWith that the
// TestSetOperations data is too dense to cover.
var X, Y intsets.Sparse
X.Insert(1)
X.Insert(1000)
X.Insert(8000)
Y.Insert(1)
Y.Insert(2000)
Y.Insert(4000)
X.IntersectionWith(&Y)
if got, want := X.String(), "{1}"; got != want {
t.Errorf("IntersectionWith: got %s, want %s", got, want)
}
}
func TestIntersects(t *testing.T) {
prng := rand.New(rand.NewSource(0))
for i := uint(0); i < 12; i++ {
X, Y := randomPset(prng, 1<<i), randomPset(prng, 1<<i)
x, y := &X.bits, &Y.bits
// test the slow way
var z intsets.Sparse
z.Copy(x)
z.IntersectionWith(y)
if got, want := x.Intersects(y), !z.IsEmpty(); got != want {
t.Errorf("Intersects(%s, %s): got %v, want %v (%s)", x, y, got, want, &z)
}
// make it false
a := x.AppendTo(nil)
for _, v := range a {
y.Remove(v)
}
if got, want := x.Intersects(y), false; got != want {
t.Errorf("Intersects: got %v, want %v", got, want)
}
// make it true
if x.IsEmpty() {
continue
}
i := prng.Intn(len(a))
y.Insert(a[i])
if got, want := x.Intersects(y), true; got != want {
t.Errorf("Intersects: got %v, want %v", got, want)
}
}
}
func TestSubsetOf(t *testing.T) {
prng := rand.New(rand.NewSource(0))
for i := uint(0); i < 12; i++ {
X, Y := randomPset(prng, 1<<i), randomPset(prng, 1<<i)
x, y := &X.bits, &Y.bits
// test the slow way
var z intsets.Sparse
z.Copy(x)
z.DifferenceWith(y)
if got, want := x.SubsetOf(y), z.IsEmpty(); got != want {
t.Errorf("SubsetOf: got %v, want %v", got, want)
}
// make it true
y.UnionWith(x)
if got, want := x.SubsetOf(y), true; got != want {
t.Errorf("SubsetOf: got %v, want %v", got, want)
}
// make it false
if x.IsEmpty() {
continue
}
a := x.AppendTo(nil)
i := prng.Intn(len(a))
y.Remove(a[i])
if got, want := x.SubsetOf(y), false; got != want {
t.Errorf("SubsetOf: got %v, want %v", got, want)
}
}
}
func TestBitString(t *testing.T) {
for _, test := range []struct {
input []int
want string
}{
{nil, "0"},
{[]int{0}, "1"},
{[]int{0, 4, 5}, "110001"},
{[]int{0, 7, 177}, "1" + strings.Repeat("0", 169) + "10000001"},
{[]int{-3, 0, 4, 5}, "110001.001"},
{[]int{-3}, "0.001"},
} {
var set intsets.Sparse
for _, x := range test.input {
set.Insert(x)
}
if got := set.BitString(); got != test.want {
t.Errorf("BitString(%s) = %s, want %s", set.String(), got, test.want)
}
}
}
func TestFailFastOnShallowCopy(t *testing.T) {
var x intsets.Sparse
x.Insert(1)
y := x // shallow copy (breaks representation invariants)
defer func() {
got := fmt.Sprint(recover())
want := "interface conversion: interface {} is nil, not intsets.to_copy_a_sparse_you_must_call_its_Copy_method"
if got != want {
t.Errorf("shallow copy: recover() = %q, want %q", got, want)
}
}()
y.String() // panics
t.Error("didn't panic as expected")
}
// -- Benchmarks -------------------------------------------------------
// TODO(adonovan):
// - Add benchmarks of each method.
// - Gather set distributions from pointer analysis.
// - Measure memory usage.
func benchmarkInsertProbeSparse(b *testing.B, size, spread int) {
prng := rand.New(rand.NewSource(0))
// Generate our insertions and probes beforehand (we don't want to benchmark
// the prng).
insert := make([]int, size)
probe := make([]int, size*2)
for i := range insert {
insert[i] = prng.Int() % spread
}
for i := range probe {
probe[i] = prng.Int() % spread
}
b.ResetTimer()
var x intsets.Sparse
for tries := 0; tries < b.N; tries++ {
x.Clear()
for _, n := range insert {
x.Insert(n)
}
hits := 0
for _, n := range probe {
if x.Has(n) {
hits++
}
}
// Use the variable so it doesn't get optimized away.
if hits > len(probe) {
b.Fatalf("%d hits, only %d probes", hits, len(probe))
}
}
}
func BenchmarkInsertProbeSparse_2_10(b *testing.B) {
benchmarkInsertProbeSparse(b, 2, 10)
}
func BenchmarkInsertProbeSparse_10_10(b *testing.B) {
benchmarkInsertProbeSparse(b, 10, 10)
}
func BenchmarkInsertProbeSparse_10_1000(b *testing.B) {
benchmarkInsertProbeSparse(b, 10, 1000)
}
func BenchmarkInsertProbeSparse_100_100(b *testing.B) {
benchmarkInsertProbeSparse(b, 100, 100)
}
func BenchmarkInsertProbeSparse_100_10000(b *testing.B) {
benchmarkInsertProbeSparse(b, 100, 1000)
}
func BenchmarkUnionDifferenceSparse(b *testing.B) {
prng := rand.New(rand.NewSource(0))
for tries := 0; tries < b.N; tries++ {
var x, y, z intsets.Sparse
for i := 0; i < 1000; i++ {
n := int(prng.Int()) % 100000
if i%2 == 0 {
x.Insert(n)
} else {
y.Insert(n)
}
}
z.Union(&x, &y)
z.Difference(&x, &y)
}
}
func BenchmarkUnionDifferenceHashTable(b *testing.B) {
prng := rand.New(rand.NewSource(0))
for tries := 0; tries < b.N; tries++ {
x, y, z := make(map[int]bool), make(map[int]bool), make(map[int]bool)
for i := 0; i < 1000; i++ {
n := int(prng.Int()) % 100000
if i%2 == 0 {
x[n] = true
} else {
y[n] = true
}
}
// union
for n := range x {
z[n] = true
}
for n := range y {
z[n] = true
}
// difference
z = make(map[int]bool)
for n := range y {
if !x[n] {
z[n] = true
}
}
}
}
func BenchmarkAppendTo(b *testing.B) {
prng := rand.New(rand.NewSource(0))
var x intsets.Sparse
for i := 0; i < 1000; i++ {
x.Insert(int(prng.Int()) % 10000)
}
var space [1000]int
for tries := 0; tries < b.N; tries++ {
x.AppendTo(space[:0])
}
}