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// 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"
. "strings"
"testing"
"unicode"
"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 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)
}
}
func TestToUpper(t *testing.T) { runStringTests(t, ToUpper, "ToUpper", upperTests) }
func TestToLower(t *testing.T) { runStringTests(t, ToLower, "ToLower", lowerTests) }
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.
a := make([]int, unicode.MaxRune+1)
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 != unicode.MaxRune+1 {
t.Error("rune count wrong in upper:", n)
}
if n := utf8.RuneCountInString(lower); n != unicode.MaxRune+1 {
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)
}
}
}