src/pkg/strings/strings_test.go - go - Git at Google

 // 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 strings_test

 import (
 	"os"
 	"reflect"
 	"strconv"
 	. "strings"
 	"testing"
 	"unicode"
 	"unsafe"
 	"utf8"
 )

 func eq(a, b []string) bool {
 	if len(a) != len(b) {
 		return false
 	}
 	for i := 0; i < len(a); i++ {
 		if a[i] != b[i] {
 			return false
 		}
 	}
 	return true
 }

 var abcd = "abcd"
 var faces = "☺☻☹"
 var commas = "1,2,3,4"
 var dots = "1....2....3....4"

 type IndexTest struct {
 	s   string
 	sep string
 	out int
 }

 var indexTests = []IndexTest{
 	{"", "", 0},
 	{"", "a", -1},
 	{"", "foo", -1},
 	{"fo", "foo", -1},
 	{"foo", "foo", 0},
 	{"oofofoofooo", "f", 2},
 	{"oofofoofooo", "foo", 4},
 	{"barfoobarfoo", "foo", 3},
 	{"foo", "", 0},
 	{"foo", "o", 1},
 	{"abcABCabc", "A", 3},
 	// cases with one byte strings - test special case in Index()
 	{"", "a", -1},
 	{"x", "a", -1},
 	{"x", "x", 0},
 	{"abc", "a", 0},
 	{"abc", "b", 1},
 	{"abc", "c", 2},
 	{"abc", "x", -1},
 }

 var lastIndexTests = []IndexTest{
 	{"", "", 0},
 	{"", "a", -1},
 	{"", "foo", -1},
 	{"fo", "foo", -1},
 	{"foo", "foo", 0},
 	{"foo", "f", 0},
 	{"oofofoofooo", "f", 7},
 	{"oofofoofooo", "foo", 7},
 	{"barfoobarfoo", "foo", 9},
 	{"foo", "", 3},
 	{"foo", "o", 2},
 	{"abcABCabc", "A", 3},
 	{"abcABCabc", "a", 6},
 }

 var indexAnyTests = []IndexTest{
 	{"", "", -1},
 	{"", "a", -1},
 	{"", "abc", -1},
 	{"a", "", -1},
 	{"a", "a", 0},
 	{"aaa", "a", 0},
 	{"abc", "xyz", -1},
 	{"abc", "xcz", 2},
 	{"a☺b☻c☹d", "uvw☻xyz", 2 + len("☺")},
 	{"aRegExp*", ".(|)*+?^$[]", 7},
 	{dots + dots + dots, " ", -1},
 }
 var lastIndexAnyTests = []IndexTest{
 	{"", "", -1},
 	{"", "a", -1},
 	{"", "abc", -1},
 	{"a", "", -1},
 	{"a", "a", 0},
 	{"aaa", "a", 2},
 	{"abc", "xyz", -1},
 	{"abc", "ab", 1},
 	{"a☺b☻c☹d", "uvw☻xyz", 2 + len("☺")},
 	{"a.RegExp*", ".(|)*+?^$[]", 8},
 	{dots + dots + dots, " ", -1},
 }

 // Execute f on each test case.  funcName should be the name of f; it's used
 // in failure reports.
 func runIndexTests(t *testing.T, f func(s, sep string) int, funcName string, testCases []IndexTest) {
 	for _, test := range testCases {
 		actual := f(test.s, test.sep)
 		if actual != test.out {
 			t.Errorf("%s(%q,%q) = %v; want %v", funcName, test.s, test.sep, actual, test.out)
 		}
 	}
 }

 func TestIndex(t *testing.T)        { runIndexTests(t, Index, "Index", indexTests) }
 func TestLastIndex(t *testing.T)    { runIndexTests(t, LastIndex, "LastIndex", lastIndexTests) }
 func TestIndexAny(t *testing.T)     { runIndexTests(t, IndexAny, "IndexAny", indexAnyTests) }
 func TestLastIndexAny(t *testing.T) { runIndexTests(t, LastIndexAny, "LastIndexAny", lastIndexAnyTests) }

 type IndexRuneTest struct {
 	s    string
 	rune int
 	out  int
 }

 var indexRuneTests = []IndexRuneTest{
 	{"a A x", 'A', 2},
 	{"some_text=some_value", '=', 9},
 	{"☺a", 'a', 3},
 	{"a☻☺b", '☺', 4},
 }

 func TestIndexRune(t *testing.T) {
 	for _, test := range indexRuneTests {
 		if actual := IndexRune(test.s, test.rune); actual != test.out {
 			t.Errorf("IndexRune(%q,%d)= %v; want %v", test.s, test.rune, actual, test.out)
 		}
 	}
 }

 const benchmarkString = "some_text=some☺value"

 func BenchmarkIndexRune(b *testing.B) {
 	if got := IndexRune(benchmarkString, '☺'); got != 14 {
 		panic("wrong index: got=" + strconv.Itoa(got))
 	}
 	for i := 0; i < b.N; i++ {
 		IndexRune(benchmarkString, '☺')
 	}
 }

 func BenchmarkIndexRuneFastPath(b *testing.B) {
 	if got := IndexRune(benchmarkString, 'v'); got != 17 {
 		panic("wrong index: got=" + strconv.Itoa(got))
 	}
 	for i := 0; i < b.N; i++ {
 		IndexRune(benchmarkString, 'v')
 	}
 }

 func BenchmarkIndex(b *testing.B) {
 	if got := Index(benchmarkString, "v"); got != 17 {
 		panic("wrong index: got=" + strconv.Itoa(got))
 	}
 	for i := 0; i < b.N; i++ {
 		Index(benchmarkString, "v")
 	}
 }


 type ExplodeTest struct {
 	s string
 	n int
 	a []string
 }

 var explodetests = []ExplodeTest{
 	{"", -1, []string{}},
 	{abcd, 4, []string{"a", "b", "c", "d"}},
 	{faces, 3, []string{"☺", "☻", "☹"}},
 	{abcd, 2, []string{"a", "bcd"}},
 }

 func TestExplode(t *testing.T) {
 	for _, tt := range explodetests {
 		a := Split(tt.s, "", tt.n)
 		if !eq(a, tt.a) {
 			t.Errorf("explode(%q, %d) = %v; want %v", tt.s, tt.n, a, tt.a)
 			continue
 		}
 		s := Join(a, "")
 		if s != tt.s {
 			t.Errorf(`Join(explode(%q, %d), "") = %q`, tt.s, tt.n, s)
 		}
 	}
 }

 type SplitTest struct {
 	s   string
 	sep string
 	n   int
 	a   []string
 }

 var splittests = []SplitTest{
 	{abcd, "a", 0, nil},
 	{abcd, "a", -1, []string{"", "bcd"}},
 	{abcd, "z", -1, []string{"abcd"}},
 	{abcd, "", -1, []string{"a", "b", "c", "d"}},
 	{commas, ",", -1, []string{"1", "2", "3", "4"}},
 	{dots, "...", -1, []string{"1", ".2", ".3", ".4"}},
 	{faces, "☹", -1, []string{"☺☻", ""}},
 	{faces, "~", -1, []string{faces}},
 	{faces, "", -1, []string{"☺", "☻", "☹"}},
 	{"1 2 3 4", " ", 3, []string{"1", "2", "3 4"}},
 	{"1 2", " ", 3, []string{"1", "2"}},
 	{"123", "", 2, []string{"1", "23"}},
 	{"123", "", 17, []string{"1", "2", "3"}},
 }

 func TestSplit(t *testing.T) {
 	for _, tt := range splittests {
 		a := Split(tt.s, tt.sep, tt.n)
 		if !eq(a, tt.a) {
 			t.Errorf("Split(%q, %q, %d) = %v; want %v", tt.s, tt.sep, tt.n, a, tt.a)
 			continue
 		}
 		if tt.n == 0 {
 			continue
 		}
 		s := Join(a, tt.sep)
 		if s != tt.s {
 			t.Errorf("Join(Split(%q, %q, %d), %q) = %q", tt.s, tt.sep, tt.n, tt.sep, s)
 		}
 	}
 }

 var splitaftertests = []SplitTest{
 	{abcd, "a", -1, []string{"a", "bcd"}},
 	{abcd, "z", -1, []string{"abcd"}},
 	{abcd, "", -1, []string{"a", "b", "c", "d"}},
 	{commas, ",", -1, []string{"1,", "2,", "3,", "4"}},
 	{dots, "...", -1, []string{"1...", ".2...", ".3...", ".4"}},
 	{faces, "☹", -1, []string{"☺☻☹", ""}},
 	{faces, "~", -1, []string{faces}},
 	{faces, "", -1, []string{"☺", "☻", "☹"}},
 	{"1 2 3 4", " ", 3, []string{"1 ", "2 ", "3 4"}},
 	{"1 2 3", " ", 3, []string{"1 ", "2 ", "3"}},
 	{"1 2", " ", 3, []string{"1 ", "2"}},
 	{"123", "", 2, []string{"1", "23"}},
 	{"123", "", 17, []string{"1", "2", "3"}},
 }

 func TestSplitAfter(t *testing.T) {
 	for _, tt := range splitaftertests {
 		a := SplitAfter(tt.s, tt.sep, tt.n)
 		if !eq(a, tt.a) {
 			t.Errorf(`Split(%q, %q, %d) = %v; want %v`, tt.s, tt.sep, tt.n, a, tt.a)
 			continue
 		}
 		s := Join(a, "")
 		if s != tt.s {
 			t.Errorf(`Join(Split(%q, %q, %d), %q) = %q`, tt.s, tt.sep, tt.n, tt.sep, s)
 		}
 	}
 }

 type FieldsTest struct {
 	s string
 	a []string
 }

 var fieldstests = []FieldsTest{
 	{"", []string{}},
 	{" ", []string{}},
 	{" \t ", []string{}},
 	{"  abc  ", []string{"abc"}},
 	{"1 2 3 4", []string{"1", "2", "3", "4"}},
 	{"1  2  3  4", []string{"1", "2", "3", "4"}},
 	{"1\t\t2\t\t3\t4", []string{"1", "2", "3", "4"}},
 	{"1\u20002\u20013\u20024", []string{"1", "2", "3", "4"}},
 	{"\u2000\u2001\u2002", []string{}},
 	{"\n™\t™\n", []string{"™", "™"}},
 	{faces, []string{faces}},
 }

 func TestFields(t *testing.T) {
 	for _, tt := range fieldstests {
 		a := Fields(tt.s)
 		if !eq(a, tt.a) {
 			t.Errorf("Fields(%q) = %v; want %v", tt.s, a, tt.a)
 			continue
 		}
 	}
 }

 func TestFieldsFunc(t *testing.T) {
 	pred := func(c int) bool { return c == 'X' }
 	var fieldsFuncTests = []FieldsTest{
 		{"", []string{}},
 		{"XX", []string{}},
 		{"XXhiXXX", []string{"hi"}},
 		{"aXXbXXXcX", []string{"a", "b", "c"}},
 	}
 	for _, tt := range fieldsFuncTests {
 		a := FieldsFunc(tt.s, pred)
 		if !eq(a, tt.a) {
 			t.Errorf("FieldsFunc(%q) = %v, want %v", tt.s, a, tt.a)
 		}
 	}
 }


 // Test case for any function which accepts and returns a single string.
 type StringTest struct {
 	in, out string
 }

 // Execute f on each test case.  funcName should be the name of f; it's used
 // in failure reports.
 func runStringTests(t *testing.T, f func(string) string, funcName string, testCases []StringTest) {
 	for _, tc := range testCases {
 		actual := f(tc.in)
 		if actual != tc.out {
 			t.Errorf("%s(%q) = %q; want %q", funcName, tc.in, actual, tc.out)
 		}
 	}
 }

 var upperTests = []StringTest{
 	{"", ""},
 	{"abc", "ABC"},
 	{"AbC123", "ABC123"},
 	{"azAZ09_", "AZAZ09_"},
 	{"\u0250\u0250\u0250\u0250\u0250", "\u2C6F\u2C6F\u2C6F\u2C6F\u2C6F"}, // grows one byte per char
 }

 var lowerTests = []StringTest{
 	{"", ""},
 	{"abc", "abc"},
 	{"AbC123", "abc123"},
 	{"azAZ09_", "azaz09_"},
 	{"\u2C6D\u2C6D\u2C6D\u2C6D\u2C6D", "\u0251\u0251\u0251\u0251\u0251"}, // shrinks one byte per char
 }

 const space = "\t\v\r\f\n\u0085\u00a0\u2000\u3000"

 var trimSpaceTests = []StringTest{
 	{"", ""},
 	{"abc", "abc"},
 	{space + "abc" + space, "abc"},
 	{" ", ""},
 	{" \t\r\n \t\t\r\r\n\n ", ""},
 	{" \t\r\n x\t\t\r\r\n\n ", "x"},
 	{" \u2000\t\r\n x\t\t\r\r\ny\n \u3000", "x\t\t\r\r\ny"},
 	{"1 \t\r\n2", "1 \t\r\n2"},
 	{" x\x80", "x\x80"},
 	{" x\xc0", "x\xc0"},
 	{"x \xc0\xc0 ", "x \xc0\xc0"},
 	{"x \xc0", "x \xc0"},
 	{"x \xc0 ", "x \xc0"},
 	{"x \xc0\xc0 ", "x \xc0\xc0"},
 	{"x ☺\xc0\xc0 ", "x ☺\xc0\xc0"},
 	{"x ☺ ", "x ☺"},
 }

 func tenRunes(rune int) string {
 	r := make([]int, 10)
 	for i := range r {
 		r[i] = rune
 	}
 	return string(r)
 }

 // User-defined self-inverse mapping function
 func rot13(rune int) int {
 	step := 13
 	if rune >= 'a' && rune <= 'z' {
 		return ((rune - 'a' + step) % 26) + 'a'
 	}
 	if rune >= 'A' && rune <= 'Z' {
 		return ((rune - 'A' + step) % 26) + 'A'
 	}
 	return rune
 }

 func TestMap(t *testing.T) {
 	// Run a couple of awful growth/shrinkage tests
 	a := tenRunes('a')
 	// 1.  Grow.  This triggers two reallocations in Map.
 	maxRune := func(rune int) int { return unicode.MaxRune }
 	m := Map(maxRune, a)
 	expect := tenRunes(unicode.MaxRune)
 	if m != expect {
 		t.Errorf("growing: expected %q got %q", expect, m)
 	}

 	// 2. Shrink
 	minRune := func(rune int) int { return 'a' }
 	m = Map(minRune, tenRunes(unicode.MaxRune))
 	expect = a
 	if m != expect {
 		t.Errorf("shrinking: expected %q got %q", expect, m)
 	}

 	// 3. Rot13
 	m = Map(rot13, "a to zed")
 	expect = "n gb mrq"
 	if m != expect {
 		t.Errorf("rot13: expected %q got %q", expect, m)
 	}

 	// 4. Rot13^2
 	m = Map(rot13, Map(rot13, "a to zed"))
 	expect = "a to zed"
 	if m != expect {
 		t.Errorf("rot13: expected %q got %q", expect, m)
 	}

 	// 5. Drop
 	dropNotLatin := func(rune int) int {
 		if unicode.Is(unicode.Latin, rune) {
 			return rune
 		}
 		return -1
 	}
 	m = Map(dropNotLatin, "Hello, 세계")
 	expect = "Hello"
 	if m != expect {
 		t.Errorf("drop: expected %q got %q", expect, m)
 	}

 	// 6. Identity
 	identity := func(rune int) int {
 		return rune
 	}
 	orig := "Input string that we expect not to be copied."
 	m = Map(identity, orig)
 	if (*reflect.StringHeader)(unsafe.Pointer(&orig)).Data !=
 		(*reflect.StringHeader)(unsafe.Pointer(&m)).Data {
 		t.Error("unexpected copy during identity map")
 	}
 }

 func TestToUpper(t *testing.T) { runStringTests(t, ToUpper, "ToUpper", upperTests) }

 func TestToLower(t *testing.T) { runStringTests(t, ToLower, "ToLower", lowerTests) }

 func BenchmarkMapNoChanges(b *testing.B) {
 	identity := func(rune int) int {
 		return rune
 	}
 	for i := 0; i < b.N; i++ {
 		Map(identity, "Some string that won't be modified.")
 	}
 }

 func TestSpecialCase(t *testing.T) {
 	lower := "abcçdefgğhıijklmnoöprsştuüvyz"
 	upper := "ABCÇDEFGĞHIİJKLMNOÖPRSŞTUÜVYZ"
 	u := ToUpperSpecial(unicode.TurkishCase, upper)
 	if u != upper {
 		t.Errorf("Upper(upper) is %s not %s", u, upper)
 	}
 	u = ToUpperSpecial(unicode.TurkishCase, lower)
 	if u != upper {
 		t.Errorf("Upper(lower) is %s not %s", u, upper)
 	}
 	l := ToLowerSpecial(unicode.TurkishCase, lower)
 	if l != lower {
 		t.Errorf("Lower(lower) is %s not %s", l, lower)
 	}
 	l = ToLowerSpecial(unicode.TurkishCase, upper)
 	if l != lower {
 		t.Errorf("Lower(upper) is %s not %s", l, lower)
 	}
 }

 func TestTrimSpace(t *testing.T) { runStringTests(t, TrimSpace, "TrimSpace", trimSpaceTests) }

 type TrimTest struct {
 	f               func(string, string) string
 	in, cutset, out string
 }

 var trimTests = []TrimTest{
 	{Trim, "abba", "a", "bb"},
 	{Trim, "abba", "ab", ""},
 	{TrimLeft, "abba", "ab", ""},
 	{TrimRight, "abba", "ab", ""},
 	{TrimLeft, "abba", "a", "bba"},
 	{TrimRight, "abba", "a", "abb"},
 	{Trim, "<tag>", "<>", "tag"},
 	{Trim, "* listitem", " *", "listitem"},
 	{Trim, `"quote"`, `"`, "quote"},
 	{Trim, "\u2C6F\u2C6F\u0250\u0250\u2C6F\u2C6F", "\u2C6F", "\u0250\u0250"},
 	//empty string tests
 	{Trim, "abba", "", "abba"},
 	{Trim, "", "123", ""},
 	{Trim, "", "", ""},
 	{TrimLeft, "abba", "", "abba"},
 	{TrimLeft, "", "123", ""},
 	{TrimLeft, "", "", ""},
 	{TrimRight, "abba", "", "abba"},
 	{TrimRight, "", "123", ""},
 	{TrimRight, "", "", ""},
 	{TrimRight, "☺\xc0", "☺", "☺\xc0"},
 }

 func TestTrim(t *testing.T) {
 	for _, tc := range trimTests {
 		actual := tc.f(tc.in, tc.cutset)
 		var name string
 		switch tc.f {
 		case Trim:
 			name = "Trim"
 		case TrimLeft:
 			name = "TrimLeft"
 		case TrimRight:
 			name = "TrimRight"
 		default:
 			t.Error("Undefined trim function")
 		}
 		if actual != tc.out {
 			t.Errorf("%s(%q, %q) = %q; want %q", name, tc.in, tc.cutset, actual, tc.out)
 		}
 	}
 }

 type predicate struct {
 	f    func(r int) bool
 	name string
 }

 var isSpace = predicate{unicode.IsSpace, "IsSpace"}
 var isDigit = predicate{unicode.IsDigit, "IsDigit"}
 var isUpper = predicate{unicode.IsUpper, "IsUpper"}
 var isValidRune = predicate{
 	func(r int) bool {
 		return r != utf8.RuneError
 	},
 	"IsValidRune",
 }

 type TrimFuncTest struct {
 	f       predicate
 	in, out string
 }

 func not(p predicate) predicate {
 	return predicate{
 		func(r int) bool {
 			return !p.f(r)
 		},
 		"not " + p.name,
 	}
 }

 var trimFuncTests = []TrimFuncTest{
 	{isSpace, space + " hello " + space, "hello"},
 	{isDigit, "\u0e50\u0e5212hello34\u0e50\u0e51", "hello"},
 	{isUpper, "\u2C6F\u2C6F\u2C6F\u2C6FABCDhelloEF\u2C6F\u2C6FGH\u2C6F\u2C6F", "hello"},
 	{not(isSpace), "hello" + space + "hello", space},
 	{not(isDigit), "hello\u0e50\u0e521234\u0e50\u0e51helo", "\u0e50\u0e521234\u0e50\u0e51"},
 	{isValidRune, "ab\xc0a\xc0cd", "\xc0a\xc0"},
 	{not(isValidRune), "\xc0a\xc0", "a"},
 }

 func TestTrimFunc(t *testing.T) {
 	for _, tc := range trimFuncTests {
 		actual := TrimFunc(tc.in, tc.f.f)
 		if actual != tc.out {
 			t.Errorf("TrimFunc(%q, %q) = %q; want %q", tc.in, tc.f.name, actual, tc.out)
 		}
 	}
 }

 type IndexFuncTest struct {
 	in          string
 	f           predicate
 	first, last int
 }

 var indexFuncTests = []IndexFuncTest{
 	{"", isValidRune, -1, -1},
 	{"abc", isDigit, -1, -1},
 	{"0123", isDigit, 0, 3},
 	{"a1b", isDigit, 1, 1},
 	{space, isSpace, 0, len(space) - 3}, // last rune in space is 3 bytes
 	{"\u0e50\u0e5212hello34\u0e50\u0e51", isDigit, 0, 18},
 	{"\u2C6F\u2C6F\u2C6F\u2C6FABCDhelloEF\u2C6F\u2C6FGH\u2C6F\u2C6F", isUpper, 0, 34},
 	{"12\u0e50\u0e52hello34\u0e50\u0e51", not(isDigit), 8, 12},

 	// tests of invalid UTF-8
 	{"\x801", isDigit, 1, 1},
 	{"\x80abc", isDigit, -1, -1},
 	{"\xc0a\xc0", isValidRune, 1, 1},
 	{"\xc0a\xc0", not(isValidRune), 0, 2},
 	{"\xc0☺\xc0", not(isValidRune), 0, 4},
 	{"\xc0☺\xc0\xc0", not(isValidRune), 0, 5},
 	{"ab\xc0a\xc0cd", not(isValidRune), 2, 4},
 	{"a\xe0\x80cd", not(isValidRune), 1, 2},
 	{"\x80\x80\x80\x80", not(isValidRune), 0, 3},
 }

 func TestIndexFunc(t *testing.T) {
 	for _, tc := range indexFuncTests {
 		first := IndexFunc(tc.in, tc.f.f)
 		if first != tc.first {
 			t.Errorf("IndexFunc(%q, %s) = %d; want %d", tc.in, tc.f.name, first, tc.first)
 		}
 		last := LastIndexFunc(tc.in, tc.f.f)
 		if last != tc.last {
 			t.Errorf("LastIndexFunc(%q, %s) = %d; want %d", tc.in, tc.f.name, last, tc.last)
 		}
 	}
 }

 func equal(m string, s1, s2 string, t *testing.T) bool {
 	if s1 == s2 {
 		return true
 	}
 	e1 := Split(s1, "", -1)
 	e2 := Split(s2, "", -1)
 	for i, c1 := range e1 {
 		if i > len(e2) {
 			break
 		}
 		r1, _ := utf8.DecodeRuneInString(c1)
 		r2, _ := utf8.DecodeRuneInString(e2[i])
 		if r1 != r2 {
 			t.Errorf("%s diff at %d: U+%04X U+%04X", m, i, r1, r2)
 		}
 	}
 	return false
 }

 func TestCaseConsistency(t *testing.T) {
 	// Make a string of all the runes.
 	numRunes := unicode.MaxRune + 1
 	if testing.Short() {
 		numRunes = 1000
 	}
 	a := make([]int, numRunes)
 	for i := range a {
 		a[i] = i
 	}
 	s := string(a)
 	// convert the cases.
 	upper := ToUpper(s)
 	lower := ToLower(s)

 	// Consistency checks
 	if n := utf8.RuneCountInString(upper); n != numRunes {
 		t.Error("rune count wrong in upper:", n)
 	}
 	if n := utf8.RuneCountInString(lower); n != numRunes {
 		t.Error("rune count wrong in lower:", n)
 	}
 	if !equal("ToUpper(upper)", ToUpper(upper), upper, t) {
 		t.Error("ToUpper(upper) consistency fail")
 	}
 	if !equal("ToLower(lower)", ToLower(lower), lower, t) {
 		t.Error("ToLower(lower) consistency fail")
 	}
 	/*
 		  These fail because of non-one-to-oneness of the data, such as multiple
 		  upper case 'I' mapping to 'i'.  We comment them out but keep them for
 		  interest.
 		  For instance: CAPITAL LETTER I WITH DOT ABOVE:
 			unicode.ToUpper(unicode.ToLower('\u0130')) != '\u0130'

 		if !equal("ToUpper(lower)", ToUpper(lower), upper, t) {
 			t.Error("ToUpper(lower) consistency fail");
 		}
 		if !equal("ToLower(upper)", ToLower(upper), lower, t) {
 			t.Error("ToLower(upper) consistency fail");
 		}
 	*/
 }

 type RepeatTest struct {
 	in, out string
 	count   int
 }

 var RepeatTests = []RepeatTest{
 	{"", "", 0},
 	{"", "", 1},
 	{"", "", 2},
 	{"-", "", 0},
 	{"-", "-", 1},
 	{"-", "----------", 10},
 	{"abc ", "abc abc abc ", 3},
 }

 func TestRepeat(t *testing.T) {
 	for _, tt := range RepeatTests {
 		a := Repeat(tt.in, tt.count)
 		if !equal("Repeat(s)", a, tt.out, t) {
 			t.Errorf("Repeat(%v, %d) = %v; want %v", tt.in, tt.count, a, tt.out)
 			continue
 		}
 	}
 }

 func runesEqual(a, b []int) bool {
 	if len(a) != len(b) {
 		return false
 	}
 	for i, r := range a {
 		if r != b[i] {
 			return false
 		}
 	}
 	return true
 }

 type RunesTest struct {
 	in    string
 	out   []int
 	lossy bool
 }

 var RunesTests = []RunesTest{
 	{"", []int{}, false},
 	{" ", []int{32}, false},
 	{"ABC", []int{65, 66, 67}, false},
 	{"abc", []int{97, 98, 99}, false},
 	{"\u65e5\u672c\u8a9e", []int{26085, 26412, 35486}, false},
 	{"ab\x80c", []int{97, 98, 0xFFFD, 99}, true},
 	{"ab\xc0c", []int{97, 98, 0xFFFD, 99}, true},
 }

 func TestRunes(t *testing.T) {
 	for _, tt := range RunesTests {
 		a := []int(tt.in)
 		if !runesEqual(a, tt.out) {
 			t.Errorf("[]int(%q) = %v; want %v", tt.in, a, tt.out)
 			continue
 		}
 		if !tt.lossy {
 			// can only test reassembly if we didn't lose information
 			s := string(a)
 			if s != tt.in {
 				t.Errorf("string([]int(%q)) = %x; want %x", tt.in, s, tt.in)
 			}
 		}
 	}
 }

 func TestReadRune(t *testing.T) {
 	testStrings := []string{"", abcd, faces, commas}
 	for _, s := range testStrings {
 		reader := NewReader(s)
 		res := ""
 		for {
 			r, _, e := reader.ReadRune()
 			if e == os.EOF {
 				break
 			}
 			if e != nil {
 				t.Errorf("Reading %q: %s", s, e)
 				break
 			}
 			res += string(r)
 		}
 		if res != s {
 			t.Errorf("Reader(%q).ReadRune() produced %q", s, res)
 		}
 	}
 }

 type ReplaceTest struct {
 	in       string
 	old, new string
 	n        int
 	out      string
 }

 var ReplaceTests = []ReplaceTest{
 	{"hello", "l", "L", 0, "hello"},
 	{"hello", "l", "L", -1, "heLLo"},
 	{"hello", "x", "X", -1, "hello"},
 	{"", "x", "X", -1, ""},
 	{"radar", "r", "<r>", -1, "<r>ada<r>"},
 	{"", "", "<>", -1, "<>"},
 	{"banana", "a", "<>", -1, "b<>n<>n<>"},
 	{"banana", "a", "<>", 1, "b<>nana"},
 	{"banana", "a", "<>", 1000, "b<>n<>n<>"},
 	{"banana", "an", "<>", -1, "b<><>a"},
 	{"banana", "ana", "<>", -1, "b<>na"},
 	{"banana", "", "<>", -1, "<>b<>a<>n<>a<>n<>a<>"},
 	{"banana", "", "<>", 10, "<>b<>a<>n<>a<>n<>a<>"},
 	{"banana", "", "<>", 6, "<>b<>a<>n<>a<>n<>a"},
 	{"banana", "", "<>", 5, "<>b<>a<>n<>a<>na"},
 	{"banana", "", "<>", 1, "<>banana"},
 	{"banana", "a", "a", -1, "banana"},
 	{"banana", "a", "a", 1, "banana"},
 	{"☺☻☹", "", "<>", -1, "<>☺<>☻<>☹<>"},
 }

 func TestReplace(t *testing.T) {
 	for _, tt := range ReplaceTests {
 		if s := Replace(tt.in, tt.old, tt.new, tt.n); s != tt.out {
 			t.Errorf("Replace(%q, %q, %q, %d) = %q, want %q", tt.in, tt.old, tt.new, tt.n, s, tt.out)
 		}
 	}
 }

 type TitleTest struct {
 	in, out string
 }

 var TitleTests = []TitleTest{
 	{"", ""},
 	{"a", "A"},
 	{" aaa aaa aaa ", " Aaa Aaa Aaa "},
 	{" Aaa Aaa Aaa ", " Aaa Aaa Aaa "},
 	{"123a456", "123a456"},
 	{"double-blind", "Double-Blind"},
 	{"ÿøû", "Ÿøû"},
 }

 func TestTitle(t *testing.T) {
 	for _, tt := range TitleTests {
 		if s := Title(tt.in); s != tt.out {
 			t.Errorf("Title(%q) = %q, want %q", tt.in, s, tt.out)
 		}
 	}
 }

 type ContainsTest struct {
 	str, substr string
 	expected    bool
 }

 var ContainsTests = []ContainsTest{
 	{"abc", "bc", true},
 	{"abc", "bcd", false},
 	{"abc", "", true},
 	{"", "a", false},
 }

 func TestContains(t *testing.T) {
 	for _, ct := range ContainsTests {
 		if Contains(ct.str, ct.substr) != ct.expected {
 			t.Errorf("Contains(%s, %s) = %v, want %v",
 				ct.str, ct.substr, !ct.expected, ct.expected)
 		}
 	}
 }
	// 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 strings_test

	import (
	"os"
	"reflect"
	"strconv"
	. "strings"
	"testing"
	"unicode"
	"unsafe"
	"utf8"
	)

	func eq(a, b []string) bool {
	if len(a) != len(b) {
	return false
	}
	for i := 0; i < len(a); i++ {
	if a[i] != b[i] {
	return false
	}
	}
	return true
	}

	var abcd = "abcd"
	var faces = "☺☻☹"
	var commas = "1,2,3,4"
	var dots = "1....2....3....4"

	type IndexTest struct {
	s string
	sep string
	out int
	}

	var indexTests = []IndexTest{
	{"", "", 0},
	{"", "a", -1},
	{"", "foo", -1},
	{"fo", "foo", -1},
	{"foo", "foo", 0},
	{"oofofoofooo", "f", 2},
	{"oofofoofooo", "foo", 4},
	{"barfoobarfoo", "foo", 3},
	{"foo", "", 0},
	{"foo", "o", 1},
	{"abcABCabc", "A", 3},
	// cases with one byte strings - test special case in Index()
	{"", "a", -1},
	{"x", "a", -1},
	{"x", "x", 0},
	{"abc", "a", 0},
	{"abc", "b", 1},
	{"abc", "c", 2},
	{"abc", "x", -1},
	}

	var lastIndexTests = []IndexTest{
	{"", "", 0},
	{"", "a", -1},
	{"", "foo", -1},
	{"fo", "foo", -1},
	{"foo", "foo", 0},
	{"foo", "f", 0},
	{"oofofoofooo", "f", 7},
	{"oofofoofooo", "foo", 7},
	{"barfoobarfoo", "foo", 9},
	{"foo", "", 3},
	{"foo", "o", 2},
	{"abcABCabc", "A", 3},
	{"abcABCabc", "a", 6},
	}

	var indexAnyTests = []IndexTest{
	{"", "", -1},
	{"", "a", -1},
	{"", "abc", -1},
	{"a", "", -1},
	{"a", "a", 0},
	{"aaa", "a", 0},
	{"abc", "xyz", -1},
	{"abc", "xcz", 2},
	{"a☺b☻c☹d", "uvw☻xyz", 2 + len("☺")},
	{"aRegExp", ".(\|)+?^$[]", 7},
	{dots + dots + dots, " ", -1},
	}
	var lastIndexAnyTests = []IndexTest{
	{"", "", -1},
	{"", "a", -1},
	{"", "abc", -1},
	{"a", "", -1},
	{"a", "a", 0},
	{"aaa", "a", 2},
	{"abc", "xyz", -1},
	{"abc", "ab", 1},
	{"a☺b☻c☹d", "uvw☻xyz", 2 + len("☺")},
	{"a.RegExp", ".(\|)+?^$[]", 8},
	{dots + dots + dots, " ", -1},
	}

	// Execute f on each test case. funcName should be the name of f; it's used
	// in failure reports.
	func runIndexTests(t *testing.T, f func(s, sep string) int, funcName string, testCases []IndexTest) {
	for _, test := range testCases {
	actual := f(test.s, test.sep)
	if actual != test.out {
	t.Errorf("%s(%q,%q) = %v; want %v", funcName, test.s, test.sep, actual, test.out)
	}
	}
	}

	func TestIndex(t *testing.T) { runIndexTests(t, Index, "Index", indexTests) }
	func TestLastIndex(t *testing.T) { runIndexTests(t, LastIndex, "LastIndex", lastIndexTests) }
	func TestIndexAny(t *testing.T) { runIndexTests(t, IndexAny, "IndexAny", indexAnyTests) }
	func TestLastIndexAny(t *testing.T) { runIndexTests(t, LastIndexAny, "LastIndexAny", lastIndexAnyTests) }

	type IndexRuneTest struct {
	s string
	rune int
	out int
	}

	var indexRuneTests = []IndexRuneTest{
	{"a A x", 'A', 2},
	{"some_text=some_value", '=', 9},
	{"☺a", 'a', 3},
	{"a☻☺b", '☺', 4},
	}

	func TestIndexRune(t *testing.T) {
	for _, test := range indexRuneTests {
	if actual := IndexRune(test.s, test.rune); actual != test.out {
	t.Errorf("IndexRune(%q,%d)= %v; want %v", test.s, test.rune, actual, test.out)
	}
	}
	}

	const benchmarkString = "some_text=some☺value"

	func BenchmarkIndexRune(b *testing.B) {
	if got := IndexRune(benchmarkString, '☺'); got != 14 {
	panic("wrong index: got=" + strconv.Itoa(got))
	}
	for i := 0; i < b.N; i++ {
	IndexRune(benchmarkString, '☺')
	}
	}

	func BenchmarkIndexRuneFastPath(b *testing.B) {
	if got := IndexRune(benchmarkString, 'v'); got != 17 {
	panic("wrong index: got=" + strconv.Itoa(got))
	}
	for i := 0; i < b.N; i++ {
	IndexRune(benchmarkString, 'v')
	}
	}

	func BenchmarkIndex(b *testing.B) {
	if got := Index(benchmarkString, "v"); got != 17 {
	panic("wrong index: got=" + strconv.Itoa(got))
	}
	for i := 0; i < b.N; i++ {
	Index(benchmarkString, "v")
	}
	}


	type ExplodeTest struct {
	s string
	n int
	a []string
	}

	var explodetests = []ExplodeTest{
	{"", -1, []string{}},
	{abcd, 4, []string{"a", "b", "c", "d"}},
	{faces, 3, []string{"☺", "☻", "☹"}},
	{abcd, 2, []string{"a", "bcd"}},
	}

	func TestExplode(t *testing.T) {
	for _, tt := range explodetests {
	a := Split(tt.s, "", tt.n)
	if !eq(a, tt.a) {
	t.Errorf("explode(%q, %d) = %v; want %v", tt.s, tt.n, a, tt.a)
	continue
	}
	s := Join(a, "")
	if s != tt.s {
	t.Errorf(`Join(explode(%q, %d), "") = %q`, tt.s, tt.n, s)
	}
	}
	}

	type SplitTest struct {
	s string
	sep string
	n int
	a []string
	}

	var splittests = []SplitTest{
	{abcd, "a", 0, nil},
	{abcd, "a", -1, []string{"", "bcd"}},
	{abcd, "z", -1, []string{"abcd"}},
	{abcd, "", -1, []string{"a", "b", "c", "d"}},
	{commas, ",", -1, []string{"1", "2", "3", "4"}},
	{dots, "...", -1, []string{"1", ".2", ".3", ".4"}},
	{faces, "☹", -1, []string{"☺☻", ""}},
	{faces, "~", -1, []string{faces}},
	{faces, "", -1, []string{"☺", "☻", "☹"}},
	{"1 2 3 4", " ", 3, []string{"1", "2", "3 4"}},
	{"1 2", " ", 3, []string{"1", "2"}},
	{"123", "", 2, []string{"1", "23"}},
	{"123", "", 17, []string{"1", "2", "3"}},
	}

	func TestSplit(t *testing.T) {
	for _, tt := range splittests {
	a := Split(tt.s, tt.sep, tt.n)
	if !eq(a, tt.a) {
	t.Errorf("Split(%q, %q, %d) = %v; want %v", tt.s, tt.sep, tt.n, a, tt.a)
	continue
	}
	if tt.n == 0 {
	continue
	}
	s := Join(a, tt.sep)
	if s != tt.s {
	t.Errorf("Join(Split(%q, %q, %d), %q) = %q", tt.s, tt.sep, tt.n, tt.sep, s)
	}
	}
	}

	var splitaftertests = []SplitTest{
	{abcd, "a", -1, []string{"a", "bcd"}},
	{abcd, "z", -1, []string{"abcd"}},
	{abcd, "", -1, []string{"a", "b", "c", "d"}},
	{commas, ",", -1, []string{"1,", "2,", "3,", "4"}},
	{dots, "...", -1, []string{"1...", ".2...", ".3...", ".4"}},
	{faces, "☹", -1, []string{"☺☻☹", ""}},
	{faces, "~", -1, []string{faces}},
	{faces, "", -1, []string{"☺", "☻", "☹"}},
	{"1 2 3 4", " ", 3, []string{"1 ", "2 ", "3 4"}},
	{"1 2 3", " ", 3, []string{"1 ", "2 ", "3"}},
	{"1 2", " ", 3, []string{"1 ", "2"}},
	{"123", "", 2, []string{"1", "23"}},
	{"123", "", 17, []string{"1", "2", "3"}},
	}

	func TestSplitAfter(t *testing.T) {
	for _, tt := range splitaftertests {
	a := SplitAfter(tt.s, tt.sep, tt.n)
	if !eq(a, tt.a) {
	t.Errorf(`Split(%q, %q, %d) = %v; want %v`, tt.s, tt.sep, tt.n, a, tt.a)
	continue
	}
	s := Join(a, "")
	if s != tt.s {
	t.Errorf(`Join(Split(%q, %q, %d), %q) = %q`, tt.s, tt.sep, tt.n, tt.sep, s)
	}
	}
	}

	type FieldsTest struct {
	s string
	a []string
	}

	var fieldstests = []FieldsTest{
	{"", []string{}},
	{" ", []string{}},
	{" \t ", []string{}},
	{" abc ", []string{"abc"}},
	{"1 2 3 4", []string{"1", "2", "3", "4"}},
	{"1 2 3 4", []string{"1", "2", "3", "4"}},
	{"1\t\t2\t\t3\t4", []string{"1", "2", "3", "4"}},
	{"1\u20002\u20013\u20024", []string{"1", "2", "3", "4"}},
	{"\u2000\u2001\u2002", []string{}},
	{"\n™\t™\n", []string{"™", "™"}},
	{faces, []string{faces}},
	}

	func TestFields(t *testing.T) {
	for _, tt := range fieldstests {
	a := Fields(tt.s)
	if !eq(a, tt.a) {
	t.Errorf("Fields(%q) = %v; want %v", tt.s, a, tt.a)
	continue
	}
	}
	}

	func TestFieldsFunc(t *testing.T) {
	pred := func(c int) bool { return c == 'X' }
	var fieldsFuncTests = []FieldsTest{
	{"", []string{}},
	{"XX", []string{}},
	{"XXhiXXX", []string{"hi"}},
	{"aXXbXXXcX", []string{"a", "b", "c"}},
	}
	for _, tt := range fieldsFuncTests {
	a := FieldsFunc(tt.s, pred)
	if !eq(a, tt.a) {
	t.Errorf("FieldsFunc(%q) = %v, want %v", tt.s, a, tt.a)
	}
	}
	}


	// Test case for any function which accepts and returns a single string.
	type StringTest struct {
	in, out string
	}

	// Execute f on each test case. funcName should be the name of f; it's used
	// in failure reports.
	func runStringTests(t *testing.T, f func(string) string, funcName string, testCases []StringTest) {
	for _, tc := range testCases {
	actual := f(tc.in)
	if actual != tc.out {
	t.Errorf("%s(%q) = %q; want %q", funcName, tc.in, actual, tc.out)
	}
	}
	}

	var upperTests = []StringTest{
	{"", ""},
	{"abc", "ABC"},
	{"AbC123", "ABC123"},
	{"azAZ09_", "AZAZ09_"},
	{"\u0250\u0250\u0250\u0250\u0250", "\u2C6F\u2C6F\u2C6F\u2C6F\u2C6F"}, // grows one byte per char
	}

	var lowerTests = []StringTest{
	{"", ""},
	{"abc", "abc"},
	{"AbC123", "abc123"},
	{"azAZ09_", "azaz09_"},
	{"\u2C6D\u2C6D\u2C6D\u2C6D\u2C6D", "\u0251\u0251\u0251\u0251\u0251"}, // shrinks one byte per char
	}

	const space = "\t\v\r\f\n\u0085\u00a0\u2000\u3000"

	var trimSpaceTests = []StringTest{
	{"", ""},
	{"abc", "abc"},
	{space + "abc" + space, "abc"},
	{" ", ""},
	{" \t\r\n \t\t\r\r\n\n ", ""},
	{" \t\r\n x\t\t\r\r\n\n ", "x"},
	{" \u2000\t\r\n x\t\t\r\r\ny\n \u3000", "x\t\t\r\r\ny"},
	{"1 \t\r\n2", "1 \t\r\n2"},
	{" x\x80", "x\x80"},
	{" x\xc0", "x\xc0"},
	{"x \xc0\xc0 ", "x \xc0\xc0"},
	{"x \xc0", "x \xc0"},
	{"x \xc0 ", "x \xc0"},
	{"x \xc0\xc0 ", "x \xc0\xc0"},
	{"x ☺\xc0\xc0 ", "x ☺\xc0\xc0"},
	{"x ☺ ", "x ☺"},
	}

	func tenRunes(rune int) string {
	r := make([]int, 10)
	for i := range r {
	r[i] = rune
	}
	return string(r)
	}

	// User-defined self-inverse mapping function
	func rot13(rune int) int {
	step := 13
	if rune >= 'a' && rune <= 'z' {
	return ((rune - 'a' + step) % 26) + 'a'
	}
	if rune >= 'A' && rune <= 'Z' {
	return ((rune - 'A' + step) % 26) + 'A'
	}
	return rune
	}

	func TestMap(t *testing.T) {
	// Run a couple of awful growth/shrinkage tests
	a := tenRunes('a')
	// 1. Grow. This triggers two reallocations in Map.
	maxRune := func(rune int) int { return unicode.MaxRune }
	m := Map(maxRune, a)
	expect := tenRunes(unicode.MaxRune)
	if m != expect {
	t.Errorf("growing: expected %q got %q", expect, m)
	}

	// 2. Shrink
	minRune := func(rune int) int { return 'a' }
	m = Map(minRune, tenRunes(unicode.MaxRune))
	expect = a
	if m != expect {
	t.Errorf("shrinking: expected %q got %q", expect, m)
	}

	// 3. Rot13
	m = Map(rot13, "a to zed")
	expect = "n gb mrq"
	if m != expect {
	t.Errorf("rot13: expected %q got %q", expect, m)
	}

	// 4. Rot13^2
	m = Map(rot13, Map(rot13, "a to zed"))
	expect = "a to zed"
	if m != expect {
	t.Errorf("rot13: expected %q got %q", expect, m)
	}

	// 5. Drop
	dropNotLatin := func(rune int) int {
	if unicode.Is(unicode.Latin, rune) {
	return rune
	}
	return -1
	}
	m = Map(dropNotLatin, "Hello, 세계")
	expect = "Hello"
	if m != expect {
	t.Errorf("drop: expected %q got %q", expect, m)
	}

	// 6. Identity
	identity := func(rune int) int {
	return rune
	}
	orig := "Input string that we expect not to be copied."
	m = Map(identity, orig)
	if (*reflect.StringHeader)(unsafe.Pointer(&orig)).Data !=
	(*reflect.StringHeader)(unsafe.Pointer(&m)).Data {
	t.Error("unexpected copy during identity map")
	}
	}

	func TestToUpper(t *testing.T) { runStringTests(t, ToUpper, "ToUpper", upperTests) }

	func TestToLower(t *testing.T) { runStringTests(t, ToLower, "ToLower", lowerTests) }

	func BenchmarkMapNoChanges(b *testing.B) {
	identity := func(rune int) int {
	return rune
	}
	for i := 0; i < b.N; i++ {
	Map(identity, "Some string that won't be modified.")
	}
	}

	func TestSpecialCase(t *testing.T) {
	lower := "abcçdefgğhıijklmnoöprsştuüvyz"
	upper := "ABCÇDEFGĞHIİJKLMNOÖPRSŞTUÜVYZ"
	u := ToUpperSpecial(unicode.TurkishCase, upper)
	if u != upper {
	t.Errorf("Upper(upper) is %s not %s", u, upper)
	}
	u = ToUpperSpecial(unicode.TurkishCase, lower)
	if u != upper {
	t.Errorf("Upper(lower) is %s not %s", u, upper)
	}
	l := ToLowerSpecial(unicode.TurkishCase, lower)
	if l != lower {
	t.Errorf("Lower(lower) is %s not %s", l, lower)
	}
	l = ToLowerSpecial(unicode.TurkishCase, upper)
	if l != lower {
	t.Errorf("Lower(upper) is %s not %s", l, lower)
	}
	}

	func TestTrimSpace(t *testing.T) { runStringTests(t, TrimSpace, "TrimSpace", trimSpaceTests) }

	type TrimTest struct {
	f func(string, string) string
	in, cutset, out string
	}

	var trimTests = []TrimTest{
	{Trim, "abba", "a", "bb"},
	{Trim, "abba", "ab", ""},
	{TrimLeft, "abba", "ab", ""},
	{TrimRight, "abba", "ab", ""},
	{TrimLeft, "abba", "a", "bba"},
	{TrimRight, "abba", "a", "abb"},
	{Trim, "<tag>", "<>", "tag"},
	{Trim, "* listitem", " *", "listitem"},
	{Trim, `"quote"`, `"`, "quote"},
	{Trim, "\u2C6F\u2C6F\u0250\u0250\u2C6F\u2C6F", "\u2C6F", "\u0250\u0250"},
	//empty string tests
	{Trim, "abba", "", "abba"},
	{Trim, "", "123", ""},
	{Trim, "", "", ""},
	{TrimLeft, "abba", "", "abba"},
	{TrimLeft, "", "123", ""},
	{TrimLeft, "", "", ""},
	{TrimRight, "abba", "", "abba"},
	{TrimRight, "", "123", ""},
	{TrimRight, "", "", ""},
	{TrimRight, "☺\xc0", "☺", "☺\xc0"},
	}

	func TestTrim(t *testing.T) {
	for _, tc := range trimTests {
	actual := tc.f(tc.in, tc.cutset)
	var name string
	switch tc.f {
	case Trim:
	name = "Trim"
	case TrimLeft:
	name = "TrimLeft"
	case TrimRight:
	name = "TrimRight"
	default:
	t.Error("Undefined trim function")
	}
	if actual != tc.out {
	t.Errorf("%s(%q, %q) = %q; want %q", name, tc.in, tc.cutset, actual, tc.out)
	}
	}
	}

	type predicate struct {
	f func(r int) bool
	name string
	}

	var isSpace = predicate{unicode.IsSpace, "IsSpace"}
	var isDigit = predicate{unicode.IsDigit, "IsDigit"}
	var isUpper = predicate{unicode.IsUpper, "IsUpper"}
	var isValidRune = predicate{
	func(r int) bool {
	return r != utf8.RuneError
	},
	"IsValidRune",
	}

	type TrimFuncTest struct {
	f predicate
	in, out string
	}

	func not(p predicate) predicate {
	return predicate{
	func(r int) bool {
	return !p.f(r)
	},
	"not " + p.name,
	}
	}

	var trimFuncTests = []TrimFuncTest{
	{isSpace, space + " hello " + space, "hello"},
	{isDigit, "\u0e50\u0e5212hello34\u0e50\u0e51", "hello"},
	{isUpper, "\u2C6F\u2C6F\u2C6F\u2C6FABCDhelloEF\u2C6F\u2C6FGH\u2C6F\u2C6F", "hello"},
	{not(isSpace), "hello" + space + "hello", space},
	{not(isDigit), "hello\u0e50\u0e521234\u0e50\u0e51helo", "\u0e50\u0e521234\u0e50\u0e51"},
	{isValidRune, "ab\xc0a\xc0cd", "\xc0a\xc0"},
	{not(isValidRune), "\xc0a\xc0", "a"},
	}

	func TestTrimFunc(t *testing.T) {
	for _, tc := range trimFuncTests {
	actual := TrimFunc(tc.in, tc.f.f)
	if actual != tc.out {
	t.Errorf("TrimFunc(%q, %q) = %q; want %q", tc.in, tc.f.name, actual, tc.out)
	}
	}
	}

	type IndexFuncTest struct {
	in string
	f predicate
	first, last int
	}

	var indexFuncTests = []IndexFuncTest{
	{"", isValidRune, -1, -1},
	{"abc", isDigit, -1, -1},
	{"0123", isDigit, 0, 3},
	{"a1b", isDigit, 1, 1},
	{space, isSpace, 0, len(space) - 3}, // last rune in space is 3 bytes
	{"\u0e50\u0e5212hello34\u0e50\u0e51", isDigit, 0, 18},
	{"\u2C6F\u2C6F\u2C6F\u2C6FABCDhelloEF\u2C6F\u2C6FGH\u2C6F\u2C6F", isUpper, 0, 34},
	{"12\u0e50\u0e52hello34\u0e50\u0e51", not(isDigit), 8, 12},

	// tests of invalid UTF-8
	{"\x801", isDigit, 1, 1},
	{"\x80abc", isDigit, -1, -1},
	{"\xc0a\xc0", isValidRune, 1, 1},
	{"\xc0a\xc0", not(isValidRune), 0, 2},
	{"\xc0☺\xc0", not(isValidRune), 0, 4},
	{"\xc0☺\xc0\xc0", not(isValidRune), 0, 5},
	{"ab\xc0a\xc0cd", not(isValidRune), 2, 4},
	{"a\xe0\x80cd", not(isValidRune), 1, 2},
	{"\x80\x80\x80\x80", not(isValidRune), 0, 3},
	}

	func TestIndexFunc(t *testing.T) {
	for _, tc := range indexFuncTests {
	first := IndexFunc(tc.in, tc.f.f)
	if first != tc.first {
	t.Errorf("IndexFunc(%q, %s) = %d; want %d", tc.in, tc.f.name, first, tc.first)
	}
	last := LastIndexFunc(tc.in, tc.f.f)
	if last != tc.last {
	t.Errorf("LastIndexFunc(%q, %s) = %d; want %d", tc.in, tc.f.name, last, tc.last)
	}
	}
	}

	func equal(m string, s1, s2 string, t *testing.T) bool {
	if s1 == s2 {
	return true
	}
	e1 := Split(s1, "", -1)
	e2 := Split(s2, "", -1)
	for i, c1 := range e1 {
	if i > len(e2) {
	break
	}
	r1, _ := utf8.DecodeRuneInString(c1)
	r2, _ := utf8.DecodeRuneInString(e2[i])
	if r1 != r2 {
	t.Errorf("%s diff at %d: U+%04X U+%04X", m, i, r1, r2)
	}
	}
	return false
	}

	func TestCaseConsistency(t *testing.T) {
	// Make a string of all the runes.
	numRunes := unicode.MaxRune + 1
	if testing.Short() {
	numRunes = 1000
	}
	a := make([]int, numRunes)
	for i := range a {
	a[i] = i
	}
	s := string(a)
	// convert the cases.
	upper := ToUpper(s)
	lower := ToLower(s)

	// Consistency checks
	if n := utf8.RuneCountInString(upper); n != numRunes {
	t.Error("rune count wrong in upper:", n)
	}
	if n := utf8.RuneCountInString(lower); n != numRunes {
	t.Error("rune count wrong in lower:", n)
	}
	if !equal("ToUpper(upper)", ToUpper(upper), upper, t) {
	t.Error("ToUpper(upper) consistency fail")
	}
	if !equal("ToLower(lower)", ToLower(lower), lower, t) {
	t.Error("ToLower(lower) consistency fail")
	}
	/*
	These fail because of non-one-to-oneness of the data, such as multiple
	upper case 'I' mapping to 'i'. We comment them out but keep them for
	interest.
	For instance: CAPITAL LETTER I WITH DOT ABOVE:
	unicode.ToUpper(unicode.ToLower('\u0130')) != '\u0130'

	if !equal("ToUpper(lower)", ToUpper(lower), upper, t) {
	t.Error("ToUpper(lower) consistency fail");
	}
	if !equal("ToLower(upper)", ToLower(upper), lower, t) {
	t.Error("ToLower(upper) consistency fail");
	}
	*/
	}

	type RepeatTest struct {
	in, out string
	count int
	}

	var RepeatTests = []RepeatTest{
	{"", "", 0},
	{"", "", 1},
	{"", "", 2},
	{"-", "", 0},
	{"-", "-", 1},
	{"-", "----------", 10},
	{"abc ", "abc abc abc ", 3},
	}

	func TestRepeat(t *testing.T) {
	for _, tt := range RepeatTests {
	a := Repeat(tt.in, tt.count)
	if !equal("Repeat(s)", a, tt.out, t) {
	t.Errorf("Repeat(%v, %d) = %v; want %v", tt.in, tt.count, a, tt.out)
	continue
	}
	}
	}

	func runesEqual(a, b []int) bool {
	if len(a) != len(b) {
	return false
	}
	for i, r := range a {
	if r != b[i] {
	return false
	}
	}
	return true
	}

	type RunesTest struct {
	in string
	out []int
	lossy bool
	}

	var RunesTests = []RunesTest{
	{"", []int{}, false},
	{" ", []int{32}, false},
	{"ABC", []int{65, 66, 67}, false},
	{"abc", []int{97, 98, 99}, false},
	{"\u65e5\u672c\u8a9e", []int{26085, 26412, 35486}, false},
	{"ab\x80c", []int{97, 98, 0xFFFD, 99}, true},
	{"ab\xc0c", []int{97, 98, 0xFFFD, 99}, true},
	}

	func TestRunes(t *testing.T) {
	for _, tt := range RunesTests {
	a := []int(tt.in)
	if !runesEqual(a, tt.out) {
	t.Errorf("[]int(%q) = %v; want %v", tt.in, a, tt.out)
	continue
	}
	if !tt.lossy {
	// can only test reassembly if we didn't lose information
	s := string(a)
	if s != tt.in {
	t.Errorf("string([]int(%q)) = %x; want %x", tt.in, s, tt.in)
	}
	}
	}
	}

	func TestReadRune(t *testing.T) {
	testStrings := []string{"", abcd, faces, commas}
	for _, s := range testStrings {
	reader := NewReader(s)
	res := ""
	for {
	r, _, e := reader.ReadRune()
	if e == os.EOF {
	break
	}
	if e != nil {
	t.Errorf("Reading %q: %s", s, e)
	break
	}
	res += string(r)
	}
	if res != s {
	t.Errorf("Reader(%q).ReadRune() produced %q", s, res)
	}
	}
	}

	type ReplaceTest struct {
	in string
	old, new string
	n int
	out string
	}

	var ReplaceTests = []ReplaceTest{
	{"hello", "l", "L", 0, "hello"},
	{"hello", "l", "L", -1, "heLLo"},
	{"hello", "x", "X", -1, "hello"},
	{"", "x", "X", -1, ""},
	{"radar", "r", "<r>", -1, "<r>ada<r>"},
	{"", "", "<>", -1, "<>"},
	{"banana", "a", "<>", -1, "b<>n<>n<>"},
	{"banana", "a", "<>", 1, "b<>nana"},
	{"banana", "a", "<>", 1000, "b<>n<>n<>"},
	{"banana", "an", "<>", -1, "b<><>a"},
	{"banana", "ana", "<>", -1, "b<>na"},
	{"banana", "", "<>", -1, "<>b<>a<>n<>a<>n<>a<>"},
	{"banana", "", "<>", 10, "<>b<>a<>n<>a<>n<>a<>"},
	{"banana", "", "<>", 6, "<>b<>a<>n<>a<>n<>a"},
	{"banana", "", "<>", 5, "<>b<>a<>n<>a<>na"},
	{"banana", "", "<>", 1, "<>banana"},
	{"banana", "a", "a", -1, "banana"},
	{"banana", "a", "a", 1, "banana"},
	{"☺☻☹", "", "<>", -1, "<>☺<>☻<>☹<>"},
	}

	func TestReplace(t *testing.T) {
	for _, tt := range ReplaceTests {
	if s := Replace(tt.in, tt.old, tt.new, tt.n); s != tt.out {
	t.Errorf("Replace(%q, %q, %q, %d) = %q, want %q", tt.in, tt.old, tt.new, tt.n, s, tt.out)
	}
	}
	}

	type TitleTest struct {
	in, out string
	}

	var TitleTests = []TitleTest{
	{"", ""},
	{"a", "A"},
	{" aaa aaa aaa ", " Aaa Aaa Aaa "},
	{" Aaa Aaa Aaa ", " Aaa Aaa Aaa "},
	{"123a456", "123a456"},
	{"double-blind", "Double-Blind"},
	{"ÿøû", "Ÿøû"},
	}

	func TestTitle(t *testing.T) {
	for _, tt := range TitleTests {
	if s := Title(tt.in); s != tt.out {
	t.Errorf("Title(%q) = %q, want %q", tt.in, s, tt.out)
	}
	}
	}

	type ContainsTest struct {
	str, substr string
	expected bool
	}

	var ContainsTests = []ContainsTest{
	{"abc", "bc", true},
	{"abc", "bcd", false},
	{"abc", "", true},
	{"", "a", false},
	}

	func TestContains(t *testing.T) {
	for _, ct := range ContainsTests {
	if Contains(ct.str, ct.substr) != ct.expected {
	t.Errorf("Contains(%s, %s) = %v, want %v",
	ct.str, ct.substr, !ct.expected, ct.expected)
	}
	}
	}