Adding upstream version 1.21.8.upstream/1.21.8

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1075 insertions, 0 deletions

diff --git a/src/slices/slices_test.go b/src/slices/slices_test.go
new file mode 100644
index 0000000..6984f27
--- /dev/null
+++ b/src/slices/slices_test.go
@@ -0,0 +1,1075 @@
+// Copyright 2021 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 slices
+
+import (
+	"cmp"
+	"internal/race"
+	"internal/testenv"
+	"math"
+	"strings"
+	"testing"
+)
+
+var equalIntTests = []struct {
+	s1, s2 []int
+	want   bool
+}{
+	{
+		[]int{1},
+		nil,
+		false,
+	},
+	{
+		[]int{},
+		nil,
+		true,
+	},
+	{
+		[]int{1, 2, 3},
+		[]int{1, 2, 3},
+		true,
+	},
+	{
+		[]int{1, 2, 3},
+		[]int{1, 2, 3, 4},
+		false,
+	},
+}
+
+var equalFloatTests = []struct {
+	s1, s2       []float64
+	wantEqual    bool
+	wantEqualNaN bool
+}{
+	{
+		[]float64{1, 2},
+		[]float64{1, 2},
+		true,
+		true,
+	},
+	{
+		[]float64{1, 2, math.NaN()},
+		[]float64{1, 2, math.NaN()},
+		false,
+		true,
+	},
+}
+
+func TestEqual(t *testing.T) {
+	for _, test := range equalIntTests {
+		if got := Equal(test.s1, test.s2); got != test.want {
+			t.Errorf("Equal(%v, %v) = %t, want %t", test.s1, test.s2, got, test.want)
+		}
+	}
+	for _, test := range equalFloatTests {
+		if got := Equal(test.s1, test.s2); got != test.wantEqual {
+			t.Errorf("Equal(%v, %v) = %t, want %t", test.s1, test.s2, got, test.wantEqual)
+		}
+	}
+}
+
+// equal is simply ==.
+func equal[T comparable](v1, v2 T) bool {
+	return v1 == v2
+}
+
+// equalNaN is like == except that all NaNs are equal.
+func equalNaN[T comparable](v1, v2 T) bool {
+	isNaN := func(f T) bool { return f != f }
+	return v1 == v2 || (isNaN(v1) && isNaN(v2))
+}
+
+// offByOne returns true if integers v1 and v2 differ by 1.
+func offByOne(v1, v2 int) bool {
+	return v1 == v2+1 || v1 == v2-1
+}
+
+func TestEqualFunc(t *testing.T) {
+	for _, test := range equalIntTests {
+		if got := EqualFunc(test.s1, test.s2, equal[int]); got != test.want {
+			t.Errorf("EqualFunc(%v, %v, equal[int]) = %t, want %t", test.s1, test.s2, got, test.want)
+		}
+	}
+	for _, test := range equalFloatTests {
+		if got := EqualFunc(test.s1, test.s2, equal[float64]); got != test.wantEqual {
+			t.Errorf("Equal(%v, %v, equal[float64]) = %t, want %t", test.s1, test.s2, got, test.wantEqual)
+		}
+		if got := EqualFunc(test.s1, test.s2, equalNaN[float64]); got != test.wantEqualNaN {
+			t.Errorf("Equal(%v, %v, equalNaN[float64]) = %t, want %t", test.s1, test.s2, got, test.wantEqualNaN)
+		}
+	}
+
+	s1 := []int{1, 2, 3}
+	s2 := []int{2, 3, 4}
+	if EqualFunc(s1, s1, offByOne) {
+		t.Errorf("EqualFunc(%v, %v, offByOne) = true, want false", s1, s1)
+	}
+	if !EqualFunc(s1, s2, offByOne) {
+		t.Errorf("EqualFunc(%v, %v, offByOne) = false, want true", s1, s2)
+	}
+
+	s3 := []string{"a", "b", "c"}
+	s4 := []string{"A", "B", "C"}
+	if !EqualFunc(s3, s4, strings.EqualFold) {
+		t.Errorf("EqualFunc(%v, %v, strings.EqualFold) = false, want true", s3, s4)
+	}
+
+	cmpIntString := func(v1 int, v2 string) bool {
+		return string(rune(v1)-1+'a') == v2
+	}
+	if !EqualFunc(s1, s3, cmpIntString) {
+		t.Errorf("EqualFunc(%v, %v, cmpIntString) = false, want true", s1, s3)
+	}
+}
+
+func BenchmarkEqualFunc_Large(b *testing.B) {
+	type Large [4 * 1024]byte
+
+	xs := make([]Large, 1024)
+	ys := make([]Large, 1024)
+	for i := 0; i < b.N; i++ {
+		_ = EqualFunc(xs, ys, func(x, y Large) bool { return x == y })
+	}
+}
+
+var compareIntTests = []struct {
+	s1, s2 []int
+	want   int
+}{
+	{
+		[]int{1},
+		[]int{1},
+		0,
+	},
+	{
+		[]int{1},
+		[]int{},
+		1,
+	},
+	{
+		[]int{},
+		[]int{1},
+		-1,
+	},
+	{
+		[]int{},
+		[]int{},
+		0,
+	},
+	{
+		[]int{1, 2, 3},
+		[]int{1, 2, 3},
+		0,
+	},
+	{
+		[]int{1, 2, 3},
+		[]int{1, 2, 3, 4},
+		-1,
+	},
+	{
+		[]int{1, 2, 3, 4},
+		[]int{1, 2, 3},
+		+1,
+	},
+	{
+		[]int{1, 2, 3},
+		[]int{1, 4, 3},
+		-1,
+	},
+	{
+		[]int{1, 4, 3},
+		[]int{1, 2, 3},
+		+1,
+	},
+	{
+		[]int{1, 4, 3},
+		[]int{1, 2, 3, 8, 9},
+		+1,
+	},
+}
+
+var compareFloatTests = []struct {
+	s1, s2 []float64
+	want   int
+}{
+	{
+		[]float64{},
+		[]float64{},
+		0,
+	},
+	{
+		[]float64{1},
+		[]float64{1},
+		0,
+	},
+	{
+		[]float64{math.NaN()},
+		[]float64{math.NaN()},
+		0,
+	},
+	{
+		[]float64{1, 2, math.NaN()},
+		[]float64{1, 2, math.NaN()},
+		0,
+	},
+	{
+		[]float64{1, math.NaN(), 3},
+		[]float64{1, math.NaN(), 4},
+		-1,
+	},
+	{
+		[]float64{1, math.NaN(), 3},
+		[]float64{1, 2, 4},
+		-1,
+	},
+	{
+		[]float64{1, math.NaN(), 3},
+		[]float64{1, 2, math.NaN()},
+		-1,
+	},
+	{
+		[]float64{1, 2, 3},
+		[]float64{1, 2, math.NaN()},
+		+1,
+	},
+	{
+		[]float64{1, 2, 3},
+		[]float64{1, math.NaN(), 3},
+		+1,
+	},
+	{
+		[]float64{1, math.NaN(), 3, 4},
+		[]float64{1, 2, math.NaN()},
+		-1,
+	},
+}
+
+func TestCompare(t *testing.T) {
+	intWant := func(want bool) string {
+		if want {
+			return "0"
+		}
+		return "!= 0"
+	}
+	for _, test := range equalIntTests {
+		if got := Compare(test.s1, test.s2); (got == 0) != test.want {
+			t.Errorf("Compare(%v, %v) = %d, want %s", test.s1, test.s2, got, intWant(test.want))
+		}
+	}
+	for _, test := range equalFloatTests {
+		if got := Compare(test.s1, test.s2); (got == 0) != test.wantEqualNaN {
+			t.Errorf("Compare(%v, %v) = %d, want %s", test.s1, test.s2, got, intWant(test.wantEqualNaN))
+		}
+	}
+
+	for _, test := range compareIntTests {
+		if got := Compare(test.s1, test.s2); got != test.want {
+			t.Errorf("Compare(%v, %v) = %d, want %d", test.s1, test.s2, got, test.want)
+		}
+	}
+	for _, test := range compareFloatTests {
+		if got := Compare(test.s1, test.s2); got != test.want {
+			t.Errorf("Compare(%v, %v) = %d, want %d", test.s1, test.s2, got, test.want)
+		}
+	}
+}
+
+func equalToCmp[T comparable](eq func(T, T) bool) func(T, T) int {
+	return func(v1, v2 T) int {
+		if eq(v1, v2) {
+			return 0
+		}
+		return 1
+	}
+}
+
+func TestCompareFunc(t *testing.T) {
+	intWant := func(want bool) string {
+		if want {
+			return "0"
+		}
+		return "!= 0"
+	}
+	for _, test := range equalIntTests {
+		if got := CompareFunc(test.s1, test.s2, equalToCmp(equal[int])); (got == 0) != test.want {
+			t.Errorf("CompareFunc(%v, %v, equalToCmp(equal[int])) = %d, want %s", test.s1, test.s2, got, intWant(test.want))
+		}
+	}
+	for _, test := range equalFloatTests {
+		if got := CompareFunc(test.s1, test.s2, equalToCmp(equal[float64])); (got == 0) != test.wantEqual {
+			t.Errorf("CompareFunc(%v, %v, equalToCmp(equal[float64])) = %d, want %s", test.s1, test.s2, got, intWant(test.wantEqual))
+		}
+	}
+
+	for _, test := range compareIntTests {
+		if got := CompareFunc(test.s1, test.s2, cmp.Compare[int]); got != test.want {
+			t.Errorf("CompareFunc(%v, %v, cmp[int]) = %d, want %d", test.s1, test.s2, got, test.want)
+		}
+	}
+	for _, test := range compareFloatTests {
+		if got := CompareFunc(test.s1, test.s2, cmp.Compare[float64]); got != test.want {
+			t.Errorf("CompareFunc(%v, %v, cmp[float64]) = %d, want %d", test.s1, test.s2, got, test.want)
+		}
+	}
+
+	s1 := []int{1, 2, 3}
+	s2 := []int{2, 3, 4}
+	if got := CompareFunc(s1, s2, equalToCmp(offByOne)); got != 0 {
+		t.Errorf("CompareFunc(%v, %v, offByOne) = %d, want 0", s1, s2, got)
+	}
+
+	s3 := []string{"a", "b", "c"}
+	s4 := []string{"A", "B", "C"}
+	if got := CompareFunc(s3, s4, strings.Compare); got != 1 {
+		t.Errorf("CompareFunc(%v, %v, strings.Compare) = %d, want 1", s3, s4, got)
+	}
+
+	compareLower := func(v1, v2 string) int {
+		return strings.Compare(strings.ToLower(v1), strings.ToLower(v2))
+	}
+	if got := CompareFunc(s3, s4, compareLower); got != 0 {
+		t.Errorf("CompareFunc(%v, %v, compareLower) = %d, want 0", s3, s4, got)
+	}
+
+	cmpIntString := func(v1 int, v2 string) int {
+		return strings.Compare(string(rune(v1)-1+'a'), v2)
+	}
+	if got := CompareFunc(s1, s3, cmpIntString); got != 0 {
+		t.Errorf("CompareFunc(%v, %v, cmpIntString) = %d, want 0", s1, s3, got)
+	}
+}
+
+var indexTests = []struct {
+	s    []int
+	v    int
+	want int
+}{
+	{
+		nil,
+		0,
+		-1,
+	},
+	{
+		[]int{},
+		0,
+		-1,
+	},
+	{
+		[]int{1, 2, 3},
+		2,
+		1,
+	},
+	{
+		[]int{1, 2, 2, 3},
+		2,
+		1,
+	},
+	{
+		[]int{1, 2, 3, 2},
+		2,
+		1,
+	},
+}
+
+func TestIndex(t *testing.T) {
+	for _, test := range indexTests {
+		if got := Index(test.s, test.v); got != test.want {
+			t.Errorf("Index(%v, %v) = %d, want %d", test.s, test.v, got, test.want)
+		}
+	}
+}
+
+func equalToIndex[T any](f func(T, T) bool, v1 T) func(T) bool {
+	return func(v2 T) bool {
+		return f(v1, v2)
+	}
+}
+
+func BenchmarkIndex_Large(b *testing.B) {
+	type Large [4 * 1024]byte
+
+	ss := make([]Large, 1024)
+	for i := 0; i < b.N; i++ {
+		_ = Index(ss, Large{1})
+	}
+}
+
+func TestIndexFunc(t *testing.T) {
+	for _, test := range indexTests {
+		if got := IndexFunc(test.s, equalToIndex(equal[int], test.v)); got != test.want {
+			t.Errorf("IndexFunc(%v, equalToIndex(equal[int], %v)) = %d, want %d", test.s, test.v, got, test.want)
+		}
+	}
+
+	s1 := []string{"hi", "HI"}
+	if got := IndexFunc(s1, equalToIndex(equal[string], "HI")); got != 1 {
+		t.Errorf("IndexFunc(%v, equalToIndex(equal[string], %q)) = %d, want %d", s1, "HI", got, 1)
+	}
+	if got := IndexFunc(s1, equalToIndex(strings.EqualFold, "HI")); got != 0 {
+		t.Errorf("IndexFunc(%v, equalToIndex(strings.EqualFold, %q)) = %d, want %d", s1, "HI", got, 0)
+	}
+}
+
+func BenchmarkIndexFunc_Large(b *testing.B) {
+	type Large [4 * 1024]byte
+
+	ss := make([]Large, 1024)
+	for i := 0; i < b.N; i++ {
+		_ = IndexFunc(ss, func(e Large) bool {
+			return e == Large{1}
+		})
+	}
+}
+
+func TestContains(t *testing.T) {
+	for _, test := range indexTests {
+		if got := Contains(test.s, test.v); got != (test.want != -1) {
+			t.Errorf("Contains(%v, %v) = %t, want %t", test.s, test.v, got, test.want != -1)
+		}
+	}
+}
+
+func TestContainsFunc(t *testing.T) {
+	for _, test := range indexTests {
+		if got := ContainsFunc(test.s, equalToIndex(equal[int], test.v)); got != (test.want != -1) {
+			t.Errorf("ContainsFunc(%v, equalToIndex(equal[int], %v)) = %t, want %t", test.s, test.v, got, test.want != -1)
+		}
+	}
+
+	s1 := []string{"hi", "HI"}
+	if got := ContainsFunc(s1, equalToIndex(equal[string], "HI")); got != true {
+		t.Errorf("ContainsFunc(%v, equalToContains(equal[string], %q)) = %t, want %t", s1, "HI", got, true)
+	}
+	if got := ContainsFunc(s1, equalToIndex(equal[string], "hI")); got != false {
+		t.Errorf("ContainsFunc(%v, equalToContains(strings.EqualFold, %q)) = %t, want %t", s1, "hI", got, false)
+	}
+	if got := ContainsFunc(s1, equalToIndex(strings.EqualFold, "hI")); got != true {
+		t.Errorf("ContainsFunc(%v, equalToContains(strings.EqualFold, %q)) = %t, want %t", s1, "hI", got, true)
+	}
+}
+
+var insertTests = []struct {
+	s    []int
+	i    int
+	add  []int
+	want []int
+}{
+	{
+		[]int{1, 2, 3},
+		0,
+		[]int{4},
+		[]int{4, 1, 2, 3},
+	},
+	{
+		[]int{1, 2, 3},
+		1,
+		[]int{4},
+		[]int{1, 4, 2, 3},
+	},
+	{
+		[]int{1, 2, 3},
+		3,
+		[]int{4},
+		[]int{1, 2, 3, 4},
+	},
+	{
+		[]int{1, 2, 3},
+		2,
+		[]int{4, 5},
+		[]int{1, 2, 4, 5, 3},
+	},
+}
+
+func TestInsert(t *testing.T) {
+	s := []int{1, 2, 3}
+	if got := Insert(s, 0); !Equal(got, s) {
+		t.Errorf("Insert(%v, 0) = %v, want %v", s, got, s)
+	}
+	for _, test := range insertTests {
+		copy := Clone(test.s)
+		if got := Insert(copy, test.i, test.add...); !Equal(got, test.want) {
+			t.Errorf("Insert(%v, %d, %v...) = %v, want %v", test.s, test.i, test.add, got, test.want)
+		}
+	}
+
+	if !testenv.OptimizationOff() && !race.Enabled {
+		// Allocations should be amortized.
+		const count = 50
+		n := testing.AllocsPerRun(10, func() {
+			s := []int{1, 2, 3}
+			for i := 0; i < count; i++ {
+				s = Insert(s, 0, 1)
+			}
+		})
+		if n > count/2 {
+			t.Errorf("too many allocations inserting %d elements: got %v, want less than %d", count, n, count/2)
+		}
+	}
+}
+
+func TestInsertOverlap(t *testing.T) {
+	const N = 10
+	a := make([]int, N)
+	want := make([]int, 2*N)
+	for n := 0; n <= N; n++ { // length
+		for i := 0; i <= n; i++ { // insertion point
+			for x := 0; x <= N; x++ { // start of inserted data
+				for y := x; y <= N; y++ { // end of inserted data
+					for k := 0; k < N; k++ {
+						a[k] = k
+					}
+					want = want[:0]
+					want = append(want, a[:i]...)
+					want = append(want, a[x:y]...)
+					want = append(want, a[i:n]...)
+					got := Insert(a[:n], i, a[x:y]...)
+					if !Equal(got, want) {
+						t.Errorf("Insert with overlap failed n=%d i=%d x=%d y=%d, got %v want %v", n, i, x, y, got, want)
+					}
+				}
+			}
+		}
+	}
+}
+
+var deleteTests = []struct {
+	s    []int
+	i, j int
+	want []int
+}{
+	{
+		[]int{1, 2, 3},
+		0,
+		0,
+		[]int{1, 2, 3},
+	},
+	{
+		[]int{1, 2, 3},
+		0,
+		1,
+		[]int{2, 3},
+	},
+	{
+		[]int{1, 2, 3},
+		3,
+		3,
+		[]int{1, 2, 3},
+	},
+	{
+		[]int{1, 2, 3},
+		0,
+		2,
+		[]int{3},
+	},
+	{
+		[]int{1, 2, 3},
+		0,
+		3,
+		[]int{},
+	},
+}
+
+func TestDelete(t *testing.T) {
+	for _, test := range deleteTests {
+		copy := Clone(test.s)
+		if got := Delete(copy, test.i, test.j); !Equal(got, test.want) {
+			t.Errorf("Delete(%v, %d, %d) = %v, want %v", test.s, test.i, test.j, got, test.want)
+		}
+	}
+}
+
+var deleteFuncTests = []struct {
+	s    []int
+	fn   func(int) bool
+	want []int
+}{
+	{
+		nil,
+		func(int) bool { return true },
+		nil,
+	},
+	{
+		[]int{1, 2, 3},
+		func(int) bool { return true },
+		nil,
+	},
+	{
+		[]int{1, 2, 3},
+		func(int) bool { return false },
+		[]int{1, 2, 3},
+	},
+	{
+		[]int{1, 2, 3},
+		func(i int) bool { return i > 2 },
+		[]int{1, 2},
+	},
+	{
+		[]int{1, 2, 3},
+		func(i int) bool { return i < 2 },
+		[]int{2, 3},
+	},
+	{
+		[]int{10, 2, 30},
+		func(i int) bool { return i >= 10 },
+		[]int{2},
+	},
+}
+
+func TestDeleteFunc(t *testing.T) {
+	for i, test := range deleteFuncTests {
+		copy := Clone(test.s)
+		if got := DeleteFunc(copy, test.fn); !Equal(got, test.want) {
+			t.Errorf("DeleteFunc case %d: got %v, want %v", i, got, test.want)
+		}
+	}
+}
+
+func panics(f func()) (b bool) {
+	defer func() {
+		if x := recover(); x != nil {
+			b = true
+		}
+	}()
+	f()
+	return false
+}
+
+func TestDeletePanics(t *testing.T) {
+	for _, test := range []struct {
+		name string
+		s    []int
+		i, j int
+	}{
+		{"with negative first index", []int{42}, -2, 1},
+		{"with negative second index", []int{42}, 1, -1},
+		{"with out-of-bounds first index", []int{42}, 2, 3},
+		{"with out-of-bounds second index", []int{42}, 0, 2},
+		{"with invalid i>j", []int{42}, 1, 0},
+	} {
+		if !panics(func() { _ = Delete(test.s, test.i, test.j) }) {
+			t.Errorf("Delete %s: got no panic, want panic", test.name)
+		}
+	}
+}
+
+func TestClone(t *testing.T) {
+	s1 := []int{1, 2, 3}
+	s2 := Clone(s1)
+	if !Equal(s1, s2) {
+		t.Errorf("Clone(%v) = %v, want %v", s1, s2, s1)
+	}
+	s1[0] = 4
+	want := []int{1, 2, 3}
+	if !Equal(s2, want) {
+		t.Errorf("Clone(%v) changed unexpectedly to %v", want, s2)
+	}
+	if got := Clone([]int(nil)); got != nil {
+		t.Errorf("Clone(nil) = %#v, want nil", got)
+	}
+	if got := Clone(s1[:0]); got == nil || len(got) != 0 {
+		t.Errorf("Clone(%v) = %#v, want %#v", s1[:0], got, s1[:0])
+	}
+}
+
+var compactTests = []struct {
+	name string
+	s    []int
+	want []int
+}{
+	{
+		"nil",
+		nil,
+		nil,
+	},
+	{
+		"one",
+		[]int{1},
+		[]int{1},
+	},
+	{
+		"sorted",
+		[]int{1, 2, 3},
+		[]int{1, 2, 3},
+	},
+	{
+		"1 item",
+		[]int{1, 1, 2},
+		[]int{1, 2},
+	},
+	{
+		"unsorted",
+		[]int{1, 2, 1},
+		[]int{1, 2, 1},
+	},
+	{
+		"many",
+		[]int{1, 2, 2, 3, 3, 4},
+		[]int{1, 2, 3, 4},
+	},
+}
+
+func TestCompact(t *testing.T) {
+	for _, test := range compactTests {
+		copy := Clone(test.s)
+		if got := Compact(copy); !Equal(got, test.want) {
+			t.Errorf("Compact(%v) = %v, want %v", test.s, got, test.want)
+		}
+	}
+}
+
+func BenchmarkCompact(b *testing.B) {
+	for _, c := range compactTests {
+		b.Run(c.name, func(b *testing.B) {
+			ss := make([]int, 0, 64)
+			for k := 0; k < b.N; k++ {
+				ss = ss[:0]
+				ss = append(ss, c.s...)
+				_ = Compact(ss)
+			}
+		})
+	}
+}
+
+func BenchmarkCompact_Large(b *testing.B) {
+	type Large [4 * 1024]byte
+
+	ss := make([]Large, 1024)
+	for i := 0; i < b.N; i++ {
+		_ = Compact(ss)
+	}
+}
+
+func TestCompactFunc(t *testing.T) {
+	for _, test := range compactTests {
+		copy := Clone(test.s)
+		if got := CompactFunc(copy, equal[int]); !Equal(got, test.want) {
+			t.Errorf("CompactFunc(%v, equal[int]) = %v, want %v", test.s, got, test.want)
+		}
+	}
+
+	s1 := []string{"a", "a", "A", "B", "b"}
+	copy := Clone(s1)
+	want := []string{"a", "B"}
+	if got := CompactFunc(copy, strings.EqualFold); !Equal(got, want) {
+		t.Errorf("CompactFunc(%v, strings.EqualFold) = %v, want %v", s1, got, want)
+	}
+}
+
+func BenchmarkCompactFunc_Large(b *testing.B) {
+	type Large [4 * 1024]byte
+
+	ss := make([]Large, 1024)
+	for i := 0; i < b.N; i++ {
+		_ = CompactFunc(ss, func(a, b Large) bool { return a == b })
+	}
+}
+
+func TestGrow(t *testing.T) {
+	s1 := []int{1, 2, 3}
+
+	copy := Clone(s1)
+	s2 := Grow(copy, 1000)
+	if !Equal(s1, s2) {
+		t.Errorf("Grow(%v) = %v, want %v", s1, s2, s1)
+	}
+	if cap(s2) < 1000+len(s1) {
+		t.Errorf("after Grow(%v) cap = %d, want >= %d", s1, cap(s2), 1000+len(s1))
+	}
+
+	// Test mutation of elements between length and capacity.
+	copy = Clone(s1)
+	s3 := Grow(copy[:1], 2)[:3]
+	if !Equal(s1, s3) {
+		t.Errorf("Grow should not mutate elements between length and capacity")
+	}
+	s3 = Grow(copy[:1], 1000)[:3]
+	if !Equal(s1, s3) {
+		t.Errorf("Grow should not mutate elements between length and capacity")
+	}
+
+	// Test number of allocations.
+	if n := testing.AllocsPerRun(100, func() { _ = Grow(s2, cap(s2)-len(s2)) }); n != 0 {
+		t.Errorf("Grow should not allocate when given sufficient capacity; allocated %v times", n)
+	}
+	if n := testing.AllocsPerRun(100, func() { _ = Grow(s2, cap(s2)-len(s2)+1) }); n != 1 {
+		errorf := t.Errorf
+		if race.Enabled || testenv.OptimizationOff() {
+			errorf = t.Logf // this allocates multiple times in race detector mode
+		}
+		errorf("Grow should allocate once when given insufficient capacity; allocated %v times", n)
+	}
+
+	// Test for negative growth sizes.
+	var gotPanic bool
+	func() {
+		defer func() { gotPanic = recover() != nil }()
+		_ = Grow(s1, -1)
+	}()
+	if !gotPanic {
+		t.Errorf("Grow(-1) did not panic; expected a panic")
+	}
+}
+
+func TestClip(t *testing.T) {
+	s1 := []int{1, 2, 3, 4, 5, 6}[:3]
+	orig := Clone(s1)
+	if len(s1) != 3 {
+		t.Errorf("len(%v) = %d, want 3", s1, len(s1))
+	}
+	if cap(s1) < 6 {
+		t.Errorf("cap(%v[:3]) = %d, want >= 6", orig, cap(s1))
+	}
+	s2 := Clip(s1)
+	if !Equal(s1, s2) {
+		t.Errorf("Clip(%v) = %v, want %v", s1, s2, s1)
+	}
+	if cap(s2) != 3 {
+		t.Errorf("cap(Clip(%v)) = %d, want 3", orig, cap(s2))
+	}
+}
+
+func TestReverse(t *testing.T) {
+	even := []int{3, 1, 4, 1, 5, 9} // len = 6
+	Reverse(even)
+	if want := []int{9, 5, 1, 4, 1, 3}; !Equal(even, want) {
+		t.Errorf("Reverse(even) = %v, want %v", even, want)
+	}
+
+	odd := []int{3, 1, 4, 1, 5, 9, 2} // len = 7
+	Reverse(odd)
+	if want := []int{2, 9, 5, 1, 4, 1, 3}; !Equal(odd, want) {
+		t.Errorf("Reverse(odd) = %v, want %v", odd, want)
+	}
+
+	words := strings.Fields("one two three")
+	Reverse(words)
+	if want := strings.Fields("three two one"); !Equal(words, want) {
+		t.Errorf("Reverse(words) = %v, want %v", words, want)
+	}
+
+	singleton := []string{"one"}
+	Reverse(singleton)
+	if want := []string{"one"}; !Equal(singleton, want) {
+		t.Errorf("Reverse(singeleton) = %v, want %v", singleton, want)
+	}
+
+	Reverse[[]string](nil)
+}
+
+// naiveReplace is a baseline implementation to the Replace function.
+func naiveReplace[S ~[]E, E any](s S, i, j int, v ...E) S {
+	s = Delete(s, i, j)
+	s = Insert(s, i, v...)
+	return s
+}
+
+func TestReplace(t *testing.T) {
+	for _, test := range []struct {
+		s, v []int
+		i, j int
+	}{
+		{}, // all zero value
+		{
+			s: []int{1, 2, 3, 4},
+			v: []int{5},
+			i: 1,
+			j: 2,
+		},
+		{
+			s: []int{1, 2, 3, 4},
+			v: []int{5, 6, 7, 8},
+			i: 1,
+			j: 2,
+		},
+		{
+			s: func() []int {
+				s := make([]int, 3, 20)
+				s[0] = 0
+				s[1] = 1
+				s[2] = 2
+				return s
+			}(),
+			v: []int{3, 4, 5, 6, 7},
+			i: 0,
+			j: 1,
+		},
+	} {
+		ss, vv := Clone(test.s), Clone(test.v)
+		want := naiveReplace(ss, test.i, test.j, vv...)
+		got := Replace(test.s, test.i, test.j, test.v...)
+		if !Equal(got, want) {
+			t.Errorf("Replace(%v, %v, %v, %v) = %v, want %v", test.s, test.i, test.j, test.v, got, want)
+		}
+	}
+}
+
+func TestReplacePanics(t *testing.T) {
+	for _, test := range []struct {
+		name string
+		s, v []int
+		i, j int
+	}{
+		{"indexes out of order", []int{1, 2}, []int{3}, 2, 1},
+		{"large index", []int{1, 2}, []int{3}, 1, 10},
+		{"negative index", []int{1, 2}, []int{3}, -1, 2},
+	} {
+		ss, vv := Clone(test.s), Clone(test.v)
+		if !panics(func() { _ = Replace(ss, test.i, test.j, vv...) }) {
+			t.Errorf("Replace %s: should have panicked", test.name)
+		}
+	}
+}
+
+func TestReplaceOverlap(t *testing.T) {
+	const N = 10
+	a := make([]int, N)
+	want := make([]int, 2*N)
+	for n := 0; n <= N; n++ { // length
+		for i := 0; i <= n; i++ { // insertion point 1
+			for j := i; j <= n; j++ { // insertion point 2
+				for x := 0; x <= N; x++ { // start of inserted data
+					for y := x; y <= N; y++ { // end of inserted data
+						for k := 0; k < N; k++ {
+							a[k] = k
+						}
+						want = want[:0]
+						want = append(want, a[:i]...)
+						want = append(want, a[x:y]...)
+						want = append(want, a[j:n]...)
+						got := Replace(a[:n], i, j, a[x:y]...)
+						if !Equal(got, want) {
+							t.Errorf("Insert with overlap failed n=%d i=%d j=%d x=%d y=%d, got %v want %v", n, i, j, x, y, got, want)
+						}
+					}
+				}
+			}
+		}
+	}
+}
+
+func BenchmarkReplace(b *testing.B) {
+	cases := []struct {
+		name string
+		s, v func() []int
+		i, j int
+	}{
+		{
+			name: "fast",
+			s: func() []int {
+				return make([]int, 100)
+			},
+			v: func() []int {
+				return make([]int, 20)
+			},
+			i: 10,
+			j: 40,
+		},
+		{
+			name: "slow",
+			s: func() []int {
+				return make([]int, 100)
+			},
+			v: func() []int {
+				return make([]int, 20)
+			},
+			i: 0,
+			j: 2,
+		},
+	}
+
+	for _, c := range cases {
+		b.Run("naive-"+c.name, func(b *testing.B) {
+			for k := 0; k < b.N; k++ {
+				s := c.s()
+				v := c.v()
+				_ = naiveReplace(s, c.i, c.j, v...)
+			}
+		})
+		b.Run("optimized-"+c.name, func(b *testing.B) {
+			for k := 0; k < b.N; k++ {
+				s := c.s()
+				v := c.v()
+				_ = Replace(s, c.i, c.j, v...)
+			}
+		})
+	}
+
+}
+
+func TestRotate(t *testing.T) {
+	const N = 10
+	s := make([]int, 0, N)
+	for n := 0; n < N; n++ {
+		for r := 0; r < n; r++ {
+			s = s[:0]
+			for i := 0; i < n; i++ {
+				s = append(s, i)
+			}
+			rotateLeft(s, r)
+			for i := 0; i < n; i++ {
+				if s[i] != (i+r)%n {
+					t.Errorf("expected n=%d r=%d i:%d want:%d got:%d", n, r, i, (i+r)%n, s[i])
+				}
+			}
+		}
+	}
+}
+
+func TestInsertGrowthRate(t *testing.T) {
+	b := make([]byte, 1)
+	maxCap := cap(b)
+	nGrow := 0
+	const N = 1e6
+	for i := 0; i < N; i++ {
+		b = Insert(b, len(b)-1, 0)
+		if cap(b) > maxCap {
+			maxCap = cap(b)
+			nGrow++
+		}
+	}
+	want := int(math.Log(N) / math.Log(1.25)) // 1.25 == growth rate for large slices
+	if nGrow > want {
+		t.Errorf("too many grows. got:%d want:%d", nGrow, want)
+	}
+}
+
+func TestReplaceGrowthRate(t *testing.T) {
+	b := make([]byte, 2)
+	maxCap := cap(b)
+	nGrow := 0
+	const N = 1e6
+	for i := 0; i < N; i++ {
+		b = Replace(b, len(b)-2, len(b)-1, 0, 0)
+		if cap(b) > maxCap {
+			maxCap = cap(b)
+			nGrow++
+		}
+	}
+	want := int(math.Log(N) / math.Log(1.25)) // 1.25 == growth rate for large slices
+	if nGrow > want {
+		t.Errorf("too many grows. got:%d want:%d", nGrow, want)
+	}
+}
+
+func apply[T any](v T, f func(T)) {
+	f(v)
+}
+
+// Test type inference with a named slice type.
+func TestInference(t *testing.T) {
+	s1 := []int{1, 2, 3}
+	apply(s1, Reverse)
+	if want := []int{3, 2, 1}; !Equal(s1, want) {
+		t.Errorf("Reverse(%v) = %v, want %v", []int{1, 2, 3}, s1, want)
+	}
+
+	type S []int
+	s2 := S{4, 5, 6}
+	apply(s2, Reverse)
+	if want := (S{6, 5, 4}); !Equal(s2, want) {
+		t.Errorf("Reverse(%v) = %v, want %v", S{4, 5, 6}, s2, want)
+	}
+}