Imported Upstream version 1.4upstream/1.4

1 files changed, 553 insertions, 0 deletions

diff --git a/src/sort/sort_test.go b/src/sort/sort_test.go
new file mode 100644
index 000000000..6c36f30e0
--- /dev/null
+++ b/src/sort/sort_test.go
@@ -0,0 +1,553 @@
+// Copyright 2009 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 sort_test
+
+import (
+	"fmt"
+	"math"
+	"math/rand"
+	. "sort"
+	"strconv"
+	"testing"
+)
+
+var ints = [...]int{74, 59, 238, -784, 9845, 959, 905, 0, 0, 42, 7586, -5467984, 7586}
+var float64s = [...]float64{74.3, 59.0, math.Inf(1), 238.2, -784.0, 2.3, math.NaN(), math.NaN(), math.Inf(-1), 9845.768, -959.7485, 905, 7.8, 7.8}
+var strings = [...]string{"", "Hello", "foo", "bar", "foo", "f00", "%*&^*&^&", "***"}
+
+func TestSortIntSlice(t *testing.T) {
+	data := ints
+	a := IntSlice(data[0:])
+	Sort(a)
+	if !IsSorted(a) {
+		t.Errorf("sorted %v", ints)
+		t.Errorf("   got %v", data)
+	}
+}
+
+func TestSortFloat64Slice(t *testing.T) {
+	data := float64s
+	a := Float64Slice(data[0:])
+	Sort(a)
+	if !IsSorted(a) {
+		t.Errorf("sorted %v", float64s)
+		t.Errorf("   got %v", data)
+	}
+}
+
+func TestSortStringSlice(t *testing.T) {
+	data := strings
+	a := StringSlice(data[0:])
+	Sort(a)
+	if !IsSorted(a) {
+		t.Errorf("sorted %v", strings)
+		t.Errorf("   got %v", data)
+	}
+}
+
+func TestInts(t *testing.T) {
+	data := ints
+	Ints(data[0:])
+	if !IntsAreSorted(data[0:]) {
+		t.Errorf("sorted %v", ints)
+		t.Errorf("   got %v", data)
+	}
+}
+
+func TestFloat64s(t *testing.T) {
+	data := float64s
+	Float64s(data[0:])
+	if !Float64sAreSorted(data[0:]) {
+		t.Errorf("sorted %v", float64s)
+		t.Errorf("   got %v", data)
+	}
+}
+
+func TestStrings(t *testing.T) {
+	data := strings
+	Strings(data[0:])
+	if !StringsAreSorted(data[0:]) {
+		t.Errorf("sorted %v", strings)
+		t.Errorf("   got %v", data)
+	}
+}
+
+func TestSortLarge_Random(t *testing.T) {
+	n := 1000000
+	if testing.Short() {
+		n /= 100
+	}
+	data := make([]int, n)
+	for i := 0; i < len(data); i++ {
+		data[i] = rand.Intn(100)
+	}
+	if IntsAreSorted(data) {
+		t.Fatalf("terrible rand.rand")
+	}
+	Ints(data)
+	if !IntsAreSorted(data) {
+		t.Errorf("sort didn't sort - 1M ints")
+	}
+}
+
+func TestReverseSortIntSlice(t *testing.T) {
+	data := ints
+	data1 := ints
+	a := IntSlice(data[0:])
+	Sort(a)
+	r := IntSlice(data1[0:])
+	Sort(Reverse(r))
+	for i := 0; i < len(data); i++ {
+		if a[i] != r[len(data)-1-i] {
+			t.Errorf("reverse sort didn't sort")
+		}
+		if i > len(data)/2 {
+			break
+		}
+	}
+}
+
+func BenchmarkSortString1K(b *testing.B) {
+	b.StopTimer()
+	for i := 0; i < b.N; i++ {
+		data := make([]string, 1<<10)
+		for i := 0; i < len(data); i++ {
+			data[i] = strconv.Itoa(i ^ 0x2cc)
+		}
+		b.StartTimer()
+		Strings(data)
+		b.StopTimer()
+	}
+}
+
+func BenchmarkStableString1K(b *testing.B) {
+	b.StopTimer()
+	for i := 0; i < b.N; i++ {
+		data := make([]string, 1<<10)
+		for i := 0; i < len(data); i++ {
+			data[i] = strconv.Itoa(i ^ 0x2cc)
+		}
+		b.StartTimer()
+		Stable(StringSlice(data))
+		b.StopTimer()
+	}
+}
+
+func BenchmarkSortInt1K(b *testing.B) {
+	b.StopTimer()
+	for i := 0; i < b.N; i++ {
+		data := make([]int, 1<<10)
+		for i := 0; i < len(data); i++ {
+			data[i] = i ^ 0x2cc
+		}
+		b.StartTimer()
+		Ints(data)
+		b.StopTimer()
+	}
+}
+
+func BenchmarkStableInt1K(b *testing.B) {
+	b.StopTimer()
+	for i := 0; i < b.N; i++ {
+		data := make([]int, 1<<10)
+		for i := 0; i < len(data); i++ {
+			data[i] = i ^ 0x2cc
+		}
+		b.StartTimer()
+		Stable(IntSlice(data))
+		b.StopTimer()
+	}
+}
+
+func BenchmarkSortInt64K(b *testing.B) {
+	b.StopTimer()
+	for i := 0; i < b.N; i++ {
+		data := make([]int, 1<<16)
+		for i := 0; i < len(data); i++ {
+			data[i] = i ^ 0xcccc
+		}
+		b.StartTimer()
+		Ints(data)
+		b.StopTimer()
+	}
+}
+
+func BenchmarkStableInt64K(b *testing.B) {
+	b.StopTimer()
+	for i := 0; i < b.N; i++ {
+		data := make([]int, 1<<16)
+		for i := 0; i < len(data); i++ {
+			data[i] = i ^ 0xcccc
+		}
+		b.StartTimer()
+		Stable(IntSlice(data))
+		b.StopTimer()
+	}
+}
+
+const (
+	_Sawtooth = iota
+	_Rand
+	_Stagger
+	_Plateau
+	_Shuffle
+	_NDist
+)
+
+const (
+	_Copy = iota
+	_Reverse
+	_ReverseFirstHalf
+	_ReverseSecondHalf
+	_Sorted
+	_Dither
+	_NMode
+)
+
+type testingData struct {
+	desc        string
+	t           *testing.T
+	data        []int
+	maxswap     int // number of swaps allowed
+	ncmp, nswap int
+}
+
+func (d *testingData) Len() int { return len(d.data) }
+func (d *testingData) Less(i, j int) bool {
+	d.ncmp++
+	return d.data[i] < d.data[j]
+}
+func (d *testingData) Swap(i, j int) {
+	if d.nswap >= d.maxswap {
+		d.t.Errorf("%s: used %d swaps sorting slice of %d", d.desc, d.nswap, len(d.data))
+		d.t.FailNow()
+	}
+	d.nswap++
+	d.data[i], d.data[j] = d.data[j], d.data[i]
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func lg(n int) int {
+	i := 0
+	for 1<<uint(i) < n {
+		i++
+	}
+	return i
+}
+
+func testBentleyMcIlroy(t *testing.T, sort func(Interface), maxswap func(int) int) {
+	sizes := []int{100, 1023, 1024, 1025}
+	if testing.Short() {
+		sizes = []int{100, 127, 128, 129}
+	}
+	dists := []string{"sawtooth", "rand", "stagger", "plateau", "shuffle"}
+	modes := []string{"copy", "reverse", "reverse1", "reverse2", "sort", "dither"}
+	var tmp1, tmp2 [1025]int
+	for _, n := range sizes {
+		for m := 1; m < 2*n; m *= 2 {
+			for dist := 0; dist < _NDist; dist++ {
+				j := 0
+				k := 1
+				data := tmp1[0:n]
+				for i := 0; i < n; i++ {
+					switch dist {
+					case _Sawtooth:
+						data[i] = i % m
+					case _Rand:
+						data[i] = rand.Intn(m)
+					case _Stagger:
+						data[i] = (i*m + i) % n
+					case _Plateau:
+						data[i] = min(i, m)
+					case _Shuffle:
+						if rand.Intn(m) != 0 {
+							j += 2
+							data[i] = j
+						} else {
+							k += 2
+							data[i] = k
+						}
+					}
+				}
+
+				mdata := tmp2[0:n]
+				for mode := 0; mode < _NMode; mode++ {
+					switch mode {
+					case _Copy:
+						for i := 0; i < n; i++ {
+							mdata[i] = data[i]
+						}
+					case _Reverse:
+						for i := 0; i < n; i++ {
+							mdata[i] = data[n-i-1]
+						}
+					case _ReverseFirstHalf:
+						for i := 0; i < n/2; i++ {
+							mdata[i] = data[n/2-i-1]
+						}
+						for i := n / 2; i < n; i++ {
+							mdata[i] = data[i]
+						}
+					case _ReverseSecondHalf:
+						for i := 0; i < n/2; i++ {
+							mdata[i] = data[i]
+						}
+						for i := n / 2; i < n; i++ {
+							mdata[i] = data[n-(i-n/2)-1]
+						}
+					case _Sorted:
+						for i := 0; i < n; i++ {
+							mdata[i] = data[i]
+						}
+						// Ints is known to be correct
+						// because mode Sort runs after mode _Copy.
+						Ints(mdata)
+					case _Dither:
+						for i := 0; i < n; i++ {
+							mdata[i] = data[i] + i%5
+						}
+					}
+
+					desc := fmt.Sprintf("n=%d m=%d dist=%s mode=%s", n, m, dists[dist], modes[mode])
+					d := &testingData{desc: desc, t: t, data: mdata[0:n], maxswap: maxswap(n)}
+					sort(d)
+					// Uncomment if you are trying to improve the number of compares/swaps.
+					//t.Logf("%s: ncmp=%d, nswp=%d", desc, d.ncmp, d.nswap)
+
+					// If we were testing C qsort, we'd have to make a copy
+					// of the slice and sort it ourselves and then compare
+					// x against it, to ensure that qsort was only permuting
+					// the data, not (for example) overwriting it with zeros.
+					//
+					// In go, we don't have to be so paranoid: since the only
+					// mutating method Sort can call is TestingData.swap,
+					// it suffices here just to check that the final slice is sorted.
+					if !IntsAreSorted(mdata) {
+						t.Errorf("%s: ints not sorted", desc)
+						t.Errorf("\t%v", mdata)
+						t.FailNow()
+					}
+				}
+			}
+		}
+	}
+}
+
+func TestSortBM(t *testing.T) {
+	testBentleyMcIlroy(t, Sort, func(n int) int { return n * lg(n) * 12 / 10 })
+}
+
+func TestHeapsortBM(t *testing.T) {
+	testBentleyMcIlroy(t, Heapsort, func(n int) int { return n * lg(n) * 12 / 10 })
+}
+
+func TestStableBM(t *testing.T) {
+	testBentleyMcIlroy(t, Stable, func(n int) int { return n * lg(n) * lg(n) / 3 })
+}
+
+// This is based on the "antiquicksort" implementation by M. Douglas McIlroy.
+// See http://www.cs.dartmouth.edu/~doug/mdmspe.pdf for more info.
+type adversaryTestingData struct {
+	data      []int
+	keys      map[int]int
+	candidate int
+}
+
+func (d *adversaryTestingData) Len() int { return len(d.data) }
+
+func (d *adversaryTestingData) Less(i, j int) bool {
+	if _, present := d.keys[i]; !present {
+		if _, present := d.keys[j]; !present {
+			if i == d.candidate {
+				d.keys[i] = len(d.keys)
+			} else {
+				d.keys[j] = len(d.keys)
+			}
+		}
+	}
+
+	if _, present := d.keys[i]; !present {
+		d.candidate = i
+		return false
+	}
+	if _, present := d.keys[j]; !present {
+		d.candidate = j
+		return true
+	}
+
+	return d.keys[i] >= d.keys[j]
+}
+
+func (d *adversaryTestingData) Swap(i, j int) {
+	d.data[i], d.data[j] = d.data[j], d.data[i]
+}
+
+func TestAdversary(t *testing.T) {
+	const size = 100
+	data := make([]int, size)
+	for i := 0; i < size; i++ {
+		data[i] = i
+	}
+
+	d := &adversaryTestingData{data, make(map[int]int), 0}
+	Sort(d) // This should degenerate to heapsort.
+}
+
+func TestStableInts(t *testing.T) {
+	data := ints
+	Stable(IntSlice(data[0:]))
+	if !IntsAreSorted(data[0:]) {
+		t.Errorf("nsorted %v\n   got %v", ints, data)
+	}
+}
+
+type intPairs []struct {
+	a, b int
+}
+
+// IntPairs compare on a only.
+func (d intPairs) Len() int           { return len(d) }
+func (d intPairs) Less(i, j int) bool { return d[i].a < d[j].a }
+func (d intPairs) Swap(i, j int)      { d[i], d[j] = d[j], d[i] }
+
+// Record initial order in B.
+func (d intPairs) initB() {
+	for i := range d {
+		d[i].b = i
+	}
+}
+
+// InOrder checks if a-equal elements were not reordered.
+func (d intPairs) inOrder() bool {
+	lastA, lastB := -1, 0
+	for i := 0; i < len(d); i++ {
+		if lastA != d[i].a {
+			lastA = d[i].a
+			lastB = d[i].b
+			continue
+		}
+		if d[i].b <= lastB {
+			return false
+		}
+		lastB = d[i].b
+	}
+	return true
+}
+
+func TestStability(t *testing.T) {
+	n, m := 100000, 1000
+	if testing.Short() {
+		n, m = 1000, 100
+	}
+	data := make(intPairs, n)
+
+	// random distribution
+	for i := 0; i < len(data); i++ {
+		data[i].a = rand.Intn(m)
+	}
+	if IsSorted(data) {
+		t.Fatalf("terrible rand.rand")
+	}
+	data.initB()
+	Stable(data)
+	if !IsSorted(data) {
+		t.Errorf("Stable didn't sort %d ints", n)
+	}
+	if !data.inOrder() {
+		t.Errorf("Stable wasn't stable on %d ints", n)
+	}
+
+	// already sorted
+	data.initB()
+	Stable(data)
+	if !IsSorted(data) {
+		t.Errorf("Stable shuffeled sorted %d ints (order)", n)
+	}
+	if !data.inOrder() {
+		t.Errorf("Stable shuffeled sorted %d ints (stability)", n)
+	}
+
+	// sorted reversed
+	for i := 0; i < len(data); i++ {
+		data[i].a = len(data) - i
+	}
+	data.initB()
+	Stable(data)
+	if !IsSorted(data) {
+		t.Errorf("Stable didn't sort %d ints", n)
+	}
+	if !data.inOrder() {
+		t.Errorf("Stable wasn't stable on %d ints", n)
+	}
+}
+
+var countOpsSizes = []int{1e2, 3e2, 1e3, 3e3, 1e4, 3e4, 1e5, 3e5, 1e6}
+
+func countOps(t *testing.T, algo func(Interface), name string) {
+	sizes := countOpsSizes
+	if testing.Short() {
+		sizes = sizes[:5]
+	}
+	if !testing.Verbose() {
+		t.Skip("Counting skipped as non-verbose mode.")
+	}
+	for _, n := range sizes {
+		td := testingData{
+			desc:    name,
+			t:       t,
+			data:    make([]int, n),
+			maxswap: 1<<31 - 1,
+		}
+		for i := 0; i < n; i++ {
+			td.data[i] = rand.Intn(n / 5)
+		}
+		algo(&td)
+		t.Logf("%s %8d elements: %11d Swap, %10d Less", name, n, td.nswap, td.ncmp)
+	}
+}
+
+func TestCountStableOps(t *testing.T) { countOps(t, Stable, "Stable") }
+func TestCountSortOps(t *testing.T)   { countOps(t, Sort, "Sort  ") }
+
+func bench(b *testing.B, size int, algo func(Interface), name string) {
+	b.StopTimer()
+	data := make(intPairs, size)
+	x := ^uint32(0)
+	for i := 0; i < b.N; i++ {
+		for n := size - 3; n <= size+3; n++ {
+			for i := 0; i < len(data); i++ {
+				x += x
+				x ^= 1
+				if int32(x) < 0 {
+					x ^= 0x88888eef
+				}
+				data[i].a = int(x % uint32(n/5))
+			}
+			data.initB()
+			b.StartTimer()
+			algo(data)
+			b.StopTimer()
+			if !IsSorted(data) {
+				b.Errorf("%s did not sort %d ints", name, n)
+			}
+			if name == "Stable" && !data.inOrder() {
+				b.Errorf("%s unstable on %d ints", name, n)
+			}
+		}
+	}
+}
+
+func BenchmarkSort1e2(b *testing.B)   { bench(b, 1e2, Sort, "Sort") }
+func BenchmarkStable1e2(b *testing.B) { bench(b, 1e2, Stable, "Stable") }
+func BenchmarkSort1e4(b *testing.B)   { bench(b, 1e4, Sort, "Sort") }
+func BenchmarkStable1e4(b *testing.B) { bench(b, 1e4, Stable, "Stable") }
+func BenchmarkSort1e6(b *testing.B)   { bench(b, 1e6, Sort, "Sort") }
+func BenchmarkStable1e6(b *testing.B) { bench(b, 1e6, Stable, "Stable") }