gopl-zh.github.com/vendor/gopl.io/ch11/word2/word_test.go

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2015-12-09 07:45:11 +00:00
// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
package word
import (
"fmt"
"math/rand"
"time"
)
//!+bench
import "testing"
//!-bench
//!+test
func TestIsPalindrome(t *testing.T) {
var tests = []struct {
input string
want bool
}{
{"", true},
{"a", true},
{"aa", true},
{"ab", false},
{"kayak", true},
{"detartrated", true},
{"A man, a plan, a canal: Panama", true},
{"Evil I did dwell; lewd did I live.", true},
{"Able was I ere I saw Elba", true},
{"été", true},
{"Et se resservir, ivresse reste.", true},
{"palindrome", false}, // non-palindrome
{"desserts", false}, // semi-palindrome
}
for _, test := range tests {
if got := IsPalindrome(test.input); got != test.want {
t.Errorf("IsPalindrome(%q) = %v", test.input, got)
}
}
}
//!-test
//!+bench
func BenchmarkIsPalindrome(b *testing.B) {
for i := 0; i < b.N; i++ {
IsPalindrome("A man, a plan, a canal: Panama")
}
}
//!-bench
//!+example
func ExampleIsPalindrome() {
fmt.Println(IsPalindrome("A man, a plan, a canal: Panama"))
fmt.Println(IsPalindrome("palindrome"))
// Output:
// true
// false
}
//!-example
/*
//!+random
import "math/rand"
//!-random
*/
//!+random
// randomPalindrome returns a palindrome whose length and contents
// are derived from the pseudo-random number generator rng.
func randomPalindrome(rng *rand.Rand) string {
n := rng.Intn(25) // random length up to 24
runes := make([]rune, n)
for i := 0; i < (n+1)/2; i++ {
r := rune(rng.Intn(0x1000)) // random rune up to '\u0999'
runes[i] = r
runes[n-1-i] = r
}
return string(runes)
}
func TestRandomPalindromes(t *testing.T) {
// Initialize a pseudo-random number generator.
seed := time.Now().UTC().UnixNano()
t.Logf("Random seed: %d", seed)
rng := rand.New(rand.NewSource(seed))
for i := 0; i < 1000; i++ {
p := randomPalindrome(rng)
if !IsPalindrome(p) {
t.Errorf("IsPalindrome(%q) = false", p)
}
}
}
//!-random
/*
// Answer for Exercicse 11.1: Modify randomPalindrome to exercise
// IsPalindrome's handling of punctuation and spaces.
// WARNING: the conversion r -> upper -> lower doesn't preserve
// the value of r in some cases, e.g., µ Μ, ſ S, ı I
// randomPalindrome returns a palindrome whose length and contents
// are derived from the pseudo-random number generator rng.
func randomNoisyPalindrome(rng *rand.Rand) string {
n := rng.Intn(25) // random length up to 24
runes := make([]rune, n)
for i := 0; i < (n+1)/2; i++ {
r := rune(rng.Intn(0x200)) // random rune up to \u99
runes[i] = r
r1 := r
if unicode.IsLetter(r) && unicode.IsLower(r) {
r = unicode.ToUpper(r)
if unicode.ToLower(r) != r1 {
fmt.Printf("cap? %c %c\n", r1, r)
}
}
runes[n-1-i] = r
}
return "?" + string(runes) + "!"
}
func TestRandomNoisyPalindromes(t *testing.T) {
// Initialize a pseudo-random number generator.
seed := time.Now().UTC().UnixNano()
t.Logf("Random seed: %d", seed)
rng := rand.New(rand.NewSource(seed))
n := 0
for i := 0; i < 1000; i++ {
p := randomNoisyPalindrome(rng)
if !IsPalindrome(p) {
t.Errorf("IsNoisyPalindrome(%q) = false", p)
n++
}
}
fmt.Fprintf(os.Stderr, "fail = %d\n", n)
}
*/