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b1b95e8214
I have a test helper which produces a random 8-character string consisting of mixed-case alphabetic characters; however, there's a small chance (6/26^8 == 0.0008%) that it would produce a valid 8-character hexadecimal string, which could be mistakenly recognized as an IP address, which _might_ break a test. Out of an abundance of caution, I guard against producing an 8-byte string that might be accidentally recognized as 8-byte hexadecimal notation by making sure the first & last bytes are NOT hex characters.
43 lines
1.4 KiB
Go
43 lines
1.4 KiB
Go
package testhelper
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import (
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"encoding/binary"
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"math/rand"
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"net"
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)
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// RandomIPv6Address is used for fuzz testing
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func RandomIPv6Address() net.IP {
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upperHalf := make([]byte, 8)
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lowerHalf := make([]byte, 8)
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binary.LittleEndian.PutUint64(upperHalf, rand.Uint64())
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binary.LittleEndian.PutUint64(lowerHalf, rand.Uint64())
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ipv6 := net.IP(append(upperHalf, lowerHalf...))
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// IPv6 addrs have a lot of all-zero two-byte sections
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// So we zero-out ~50% of the sections
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for i := 0; i < 8; i++ {
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if rand.Int()%2 == 0 {
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for j := 0; j < 2; j++ {
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ipv6[i*2+j] = 0
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}
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}
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}
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// avoid pathological case: an IPv4 address []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, ?, ?, ?, ?})
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ipv6[10] &= 0xfe
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return ipv6
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}
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// Random8ByteString() returns an 8-char mixed-case string consisting solely of the letters a-z.
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// the first & last characters are non-hexadecimal to avoid confusion with hexadecimal notation
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func Random8ByteString() string {
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var randomString []byte
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// 71 == ascii 'G', +32 (103) == ascii 'g'
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randomString = append(randomString, byte(71+32*rand.Intn(2)+rand.Intn(20)))
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for range 6 {
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// 65 == ascii 'A', +32 (96) == ascii 'a', there are 26 letters in the alphabet. Mix upper case, too.
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randomString = append(randomString, byte(65+32*rand.Intn(2)+rand.Intn(26)))
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}
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randomString = append(randomString, byte(71+32*rand.Intn(2)+rand.Intn(20)))
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return string(randomString)
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}
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