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nanoid_test.go
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nanoid_test.go
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// Copyright (c) 2024 Six After, Inc
//
// This source code is licensed under the Apache 2.0 License found in the
// LICENSE file in the root directory of this source tree.
package nanoid
import (
"encoding"
"errors"
"fmt"
"io"
"strconv"
"sync"
"testing"
"github.com/stretchr/testify/assert"
)
var (
// Ensure ID implements the fmt.Stringer interface
_ = fmt.Stringer(&EmptyID)
// Ensure ID implements the encoding.BinaryMarshaler interface
_ = encoding.BinaryMarshaler(&EmptyID)
// Ensure ID implements the encoding.BinaryUnmarshaler interface
_ = encoding.BinaryUnmarshaler(&EmptyID)
// Ensure ID implements the encoding.TextMarshaler interface
_ = encoding.TextMarshaler(&EmptyID)
// Ensure ID implements the encoding.TextUnmarshaler interface
_ = encoding.TextUnmarshaler(&EmptyID)
)
// TestNewWithCustomLengths tests the generation of Nano IDs with custom lengths.
func TestNewWithCustomLengths(t *testing.T) {
t.Parallel()
lengths := []int{1, 5, 10, 21, 50, 100}
for _, length := range lengths {
length := length // capture range variable
t.Run("Length_"+strconv.Itoa(length), func(t *testing.T) {
t.Parallel()
is := assert.New(t)
id, err := NewWithLength(length)
is.NoError(err, "NewWithLength(%d) should not return an error", length)
is.Equal(length, len([]rune(id)), "Generated ID should have the specified length")
is.True(isValidID(id, DefaultAlphabet), "Generated ID contains invalid characters")
})
}
}
// TestNewAndMustDefault tests the must generation of a default Nano ID.
func TestNewAndMustDefault(t *testing.T) {
t.Parallel()
is := assert.New(t)
id := Must()
is.Equal(DefaultLength, len([]rune(id)), "Generated ID should have the default length")
id = MustWithLength(DefaultLength)
is.Equal(DefaultLength, len([]rune(id)), "Generated ID should have the default length")
is.True(isValidID(id, DefaultAlphabet), "Generated ID contains invalid characters")
}
// TestNewAndMustWithCustomLengthPanic tests the must generation of a NanoID with an invalid length for panic.
func TestNewAndMustWithCustomLengthPanic(t *testing.T) {
t.Parallel()
is := assert.New(t)
is.Panics(func() {
MustWithLength(0)
})
}
// TestNewInvalidLength tests the generator's response to invalid lengths.
func TestNewInvalidLength(t *testing.T) {
t.Parallel()
invalidLengths := []int{0, -1, -10}
for _, length := range invalidLengths {
length := length // capture range variable
t.Run("InvalidLength_"+strconv.Itoa(length), func(t *testing.T) {
t.Parallel()
is := assert.New(t)
id, err := NewWithLength(length)
is.Error(err, "NewWithLength(%d) should return an error", length)
is.Empty(id, "Generated ID should be empty on error")
is.Equal(ErrInvalidLength, err, "Expected ErrInvalidLength")
})
}
}
// TestGenerateWithCustomAlphabet tests the generation of IDs with a custom alphabet.
func TestGenerateWithCustomAlphabet(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Include Unicode characters in the custom alphabet
alphabet := "abc😊🚀🌟"
const idLength = 8
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithLengthHint(idLength),
)
is.NoError(err, "NewGenerator() should not return an error with a valid custom alphabet")
id, err := gen.New(idLength)
is.NoError(err, "New(10) should not return an error")
is.Equal(idLength, len([]rune(id)), "Generated ID should have the specified length")
is.True(isValidID(id, alphabet), "Generated ID contains invalid characters")
}
// TestGenerateWithDuplicateAlphabet tests that the generator returns an error with duplicate characters.
func TestGenerateWithDuplicateAlphabet(t *testing.T) {
t.Parallel()
is := assert.New(t)
alphabet := "aabbcc😊😊"
gen, err := NewGenerator(
WithAlphabet(alphabet),
)
is.Error(err, "NewGenerator() should return an error with duplicate characters in the alphabet")
is.Nil(gen, "Interface should be nil when initialization fails")
is.Equal(ErrDuplicateCharacters, err, "Expected ErrDuplicateCharacters")
}
// TestNewGeneratorWithInvalidAlphabet tests that the generator returns an error with invalid alphabets.
func TestNewGeneratorWithInvalidAlphabet(t *testing.T) {
t.Parallel()
is := assert.New(t)
lengths := []int{1, 2, 256, 257}
mean := mean(lengths)
// Define the alphabet types to test
types := []string{"ASCII", "Unicode"}
for _, alphabetType := range types {
for _, length := range lengths {
// New the appropriate alphabet
var alphabet string
if alphabetType == "ASCII" {
alphabet = makeASCIIBasedAlphabet(length)
} else {
alphabet = makeUnicodeAlphabet(length)
}
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithLengthHint(uint16(mean)),
)
alphabetRunes := []rune(alphabet)
l := len(alphabetRunes)
switch true {
case l < MinAlphabetLength:
is.Error(err, "NewGenerator() should return an error with an invalid alphabet length")
is.Nil(gen, "Interface should be nil when initialization fails")
is.Equal(ErrAlphabetTooShort, err, "Expected ErrAlphabetTooShort")
case l > MaxAlphabetLength:
is.Error(err, "NewGenerator() should return an error with an invalid alphabet length")
is.Nil(gen, "Interface should be nil when initialization fails")
is.Equal(ErrAlphabetTooLong, err, "Expected ErrAlphabetTooLong")
default:
is.NoError(err, "NewGenerator() should not return an error when initialization succeeds")
}
}
}
}
// TestGetConfig tests the Config() method of the generator.
func TestInvalidUTF8Alphabet(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Create a byte slice with an invalid UTF-8 sequence.
// Here, 0x80 is a continuation byte, which by itself is not valid UTF-8.
alphabet := string([]byte{0x80})
gen, err := NewGenerator(
WithAlphabet(alphabet),
)
is.Error(err, "NewGenerator() should return an error with an invalid alphabet")
is.Nil(gen, "Interface should be nil when initialization fails")
is.Equal(ErrNonUTF8Alphabet, err, "Expected ErrNonUTF8Alphabet")
}
// TestUniqueness tests that multiple generated IDs are unique.
func TestUniqueness(t *testing.T) {
t.Parallel()
is := assert.New(t)
numIDs := 1000
ids := make(map[ID]struct{}, numIDs)
for i := 0; i < numIDs; i++ {
id, err := New()
is.NoError(err, "New() should not return an error")
is.NotContains(ids, id, "Duplicate ID found: %s", id)
ids[id] = struct{}{}
}
}
// TestConcurrency tests that the generator is safe for concurrent use.
func TestConcurrency(t *testing.T) {
t.Parallel()
is := assert.New(t)
numGoroutines := 100
numIDsPerGoroutine := 100
var wg sync.WaitGroup
wg.Add(numGoroutines)
ids := make(chan ID, numGoroutines*numIDsPerGoroutine)
errorsChan := make(chan error, numGoroutines*numIDsPerGoroutine)
for i := 0; i < numGoroutines; i++ {
go func() {
defer wg.Done()
for j := 0; j < numIDsPerGoroutine; j++ {
id, err := New()
if err != nil {
errorsChan <- err
continue
}
ids <- id
}
}()
}
wg.Wait()
close(ids)
close(errorsChan)
for err := range errorsChan {
is.NoError(err, "New() should not return an error in concurrent execution")
}
idSet := make(map[ID]struct{}, numGoroutines*numIDsPerGoroutine)
for id := range ids {
if _, exists := idSet[id]; exists {
is.Failf("Duplicate ID found in concurrency test", "Duplicate ID: %s", id)
}
idSet[id] = struct{}{}
}
}
// isValidID checks if all characters in the ID are within the specified alphabet.
func isValidID(id ID, alphabet string) bool {
alphabetSet := make(map[rune]struct{}, len([]rune(alphabet)))
for _, char := range alphabet {
alphabetSet[char] = struct{}{}
}
for _, char := range id {
if _, exists := alphabetSet[char]; !exists {
return false
}
}
return true
}
// cyclicReader is a helper type that cycles through a predefined set of bytes.
// It implements the io.Reader interface.
type cyclicReader struct {
data []byte
mu sync.Mutex
pos int
}
// Read fills p with bytes from the cyclicReader's data, cycling back to the start when necessary.
func (r *cyclicReader) Read(p []byte) (int, error) {
r.mu.Lock()
defer r.mu.Unlock()
if len(r.data) == 0 {
return 0, io.EOF
}
n := 0
for n < len(p) {
p[n] = r.data[r.pos]
n++
r.pos = (r.pos + 1) % len(r.data)
}
return n, nil
}
func TestCyclicReader(t *testing.T) {
expected := []byte{0, 1, 2, 3, 0, 1, 2, 3}
reader := &cyclicReader{data: []byte{0, 1, 2, 3}}
buffer := make([]byte, len(expected))
n, err := reader.Read(buffer)
assert.NoError(t, err)
assert.Equal(t, len(expected), n)
assert.Equal(t, expected, buffer)
}
// TestWithRandReader tests the WithRandReader option to ensure that the generator uses the provided random source.
func TestWithRandReader(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Define a custom alphabet
alphabet := "ABCD"
// Define a custom random source with known bytes
// For example, bytes [0,1,2,3] should map to 'A','B','C','D'
customBytes := []byte{0, 1, 2, 3}
customReader := &cyclicReader{data: customBytes}
// Initialize the generator with custom alphabet and custom random reader
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithRandReader(customReader),
)
is.NoError(err, "NewGenerator() should not return an error with valid custom alphabet and random reader")
// New ID of length 4
id, err := gen.New(4)
is.NoError(err, "New(4) should not return an error")
is.Equal("ABCD", string(id), "Generated ID should match the expected sequence 'ABCD'")
// New another ID of length 4, should cycle through customBytes again
id, err = gen.New(4)
is.NoError(err, "New(4) should not return an error on subsequent generation")
is.Equal("ABCD", string(id), "Generated ID should match the expected sequence 'ABCD' on subsequent generation")
// New ID of length 8, should cycle through customBytes twice
id, err = gen.New(8)
is.NoError(err, "New(8) should not return an error")
is.Equal("ABCDABCD", string(id), "Generated ID should match the expected sequence 'ABCDABCD' for length 8")
}
// TestWithRandReaderDifferentSequence tests the WithRandReader option with a different byte sequence and alphabet.
func TestWithRandReaderDifferentSequence(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Define a different custom alphabet
alphabet := "WXYZ"
// Define a different custom random source with known bytes
// For example, bytes [3,2,1,0] should map to 'Z','Y','X','W'
customBytes := []byte{3, 2, 1, 0}
customReader := &cyclicReader{data: customBytes}
// Initialize the generator with custom alphabet and custom random reader
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithRandReader(customReader),
)
is.NoError(err, "NewGenerator() should not return an error with valid custom alphabet and random reader")
// New ID of length 4
id, err := gen.New(4)
is.NoError(err, "New(4) should not return an error")
is.Equal("ZYXW", string(id), "Generated ID should match the expected sequence 'ZYXW'")
// New another ID of length 4, should cycle through customBytes again
id, err = gen.New(4)
is.NoError(err, "New(4) should not return an error on subsequent generation")
is.Equal("ZYXW", string(id), "Generated ID should match the expected sequence 'ZYXW' on subsequent generation")
// New ID of length 8, should cycle through customBytes twice
id, err = gen.New(8)
is.NoError(err, "New(8) should not return an error")
is.Equal("ZYXWZYXW", string(id), "Generated ID should match the expected sequence 'ZYXWZYXW' for length 8")
}
// TestWithRandReaderInsufficientBytes tests the generator's behavior when the custom reader provides insufficient bytes.
// Since cyclicReader cycles through the data, it should still work correctly.
func TestWithRandReaderInsufficientBytes(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Define a custom alphabet
alphabet := "EFGH"
// Define a custom random source with a single byte
customBytes := []byte{1} // Should map to 'F' repeatedly
customReader := &cyclicReader{data: customBytes}
// Initialize the generator with custom alphabet and custom random reader
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithRandReader(customReader),
)
is.NoError(err, "NewGenerator() should not return an error with valid custom alphabet and random reader")
// New ID of length 4, expecting 'FFFF'
id, err := gen.New(4)
is.NoError(err, "New(4) should not return an error")
is.Equal("FFFF", string(id), "Generated ID should match the expected sequence 'FFFF'")
// New ID of length 6, expecting 'FFFFFF'
id, err = gen.New(6)
is.NoError(err, "New(6) should not return an error")
is.Equal("FFFFFF", string(id), "Generated ID should match the expected sequence 'FFFFFF'")
}
// TestGenerateWithNonPowerOfTwoAlphabetLength tests ID generation with an alphabet length that is not a power of two.
func TestGenerateWithNonPowerOfTwoAlphabetLength(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Alphabet length is 10, which is not a power of two
alphabet := "ABCDEFGHIJ" // Length = 10
const idLength = 16
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithLengthHint(idLength),
)
is.NoError(err, "NewGenerator() should not return an error with a valid non-power-of-two alphabet length")
id, err := gen.New(idLength)
is.NoError(err, "gen.New(%d) should not return an error", idLength)
is.Equal(idLength, len([]rune(id)), "Generated ID should have the specified length")
is.True(isValidID(id, alphabet), "Generated ID contains invalid characters")
}
// TestGenerateWithMinimalAlphabet tests ID generation with the minimal valid alphabet size.
func TestGenerateWithMinimalAlphabet(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Minimal valid alphabet length is 2
alphabet := "01"
const idLength = 32
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithLengthHint(idLength),
)
is.NoError(err, "NewGenerator() should not return an error with the minimal alphabet length")
id, err := gen.New(idLength)
is.NoError(err, "gen.New(%d) should not return an error", idLength)
is.Equal(idLength, len([]rune(id)), "Generated ID should have the specified length")
is.True(isValidID(id, alphabet), "Generated ID contains invalid characters")
}
// TestGenerateWithMaximalAlphabet tests the generation of IDs with a large alphabet size.
func TestGenerateWithMaximalAlphabet(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Generate a maximal alphabet of 256 unique runes that form a valid UTF-8 string
var alphabet string
for i := 0; i < MaxAlphabetLength; i++ {
// Ensure each rune is a valid UTF-8 character
// Runes from 0x0000 to 0x00FF are valid and can be represented in UTF-8
alphabet += string(rune(i))
}
const idLength = 128
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithLengthHint(idLength),
)
is.NoError(err, "NewGenerator() should not return an error with a maximal alphabet length")
id, err := gen.New(idLength)
is.NoError(err, "gen.New(%d) should not return an error", idLength)
is.Equal(idLength, len([]rune(id)), "Generated ID should have the specified length")
is.True(isValidID(id, alphabet), "Generated ID contains invalid characters")
}
// TestGenerateWithCustomRandReaderReturningError tests generator behavior when the custom random reader returns an error.
func TestGenerateWithCustomRandReaderReturningError(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Define a custom random reader that always returns an error
failingReader := &failingRandReader{}
const idLength = 8
// Initialize the generator with a valid alphabet and the failing random reader
alphabet := "ABCDEFGH"
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithRandReader(failingReader),
WithLengthHint(idLength),
)
is.NoError(err, "NewGenerator() should not return an error with a valid custom alphabet")
// Attempt to generate an ID
id, err := gen.New(idLength)
is.Error(err, "gen.New() should return an error when random reader fails")
is.Empty(id, "Generated ID should be empty on error")
is.Equal(io.ErrUnexpectedEOF, err, "Expected io.ErrUnexpectedEOF from failingRandReader")
}
// failingRandReader is a custom io.Reader that always returns an error.
type failingRandReader struct{}
// Read implements the io.Reader interface and always returns an error.
func (f *failingRandReader) Read(_ []byte) (int, error) {
return 0, io.ErrUnexpectedEOF
}
// TestGenerateWithNonASCIIAlphabet tests ID generation with a Unicode alphabet when isASCII is false.
func TestGenerateWithNonASCIIAlphabet(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Define a Unicode alphabet with emojis and special characters
alphabet := "αβγδε😊🚀🌟"
const idLength = 10
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithLengthHint(idLength),
)
is.NoError(err, "NewGenerator() should not return an error with a valid Unicode alphabet and isASCII=false")
id, err := gen.New(idLength)
is.NoError(err, "gen.New(%d) should not return an error", idLength)
is.Equal(idLength, len([]rune(id)), "Generated ID should have the specified length")
is.True(isValidID(id, alphabet), "Generated ID contains invalid characters")
}
// TestGenerateWithSpecialCharactersInAlphabet tests ID generation with an alphabet containing special characters and emojis.
func TestGenerateWithSpecialCharactersInAlphabet(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Alphabet with special characters and emojis
alphabet := "!@#$%^&*()_+😊🚀"
const idLength = 12
gen, err := NewGenerator(
WithAlphabet(alphabet),
)
is.NoError(err, "NewGenerator() should not return an error with a special characters alphabet")
id, err := gen.New(idLength)
is.NoError(err, "gen.New(%d) should not return an error", idLength)
is.Equal(idLength, len([]rune(id)), "Generated ID should have the specified length")
is.True(isValidID(id, alphabet), "Generated ID contains invalid characters")
}
// TestGenerateWithVeryLargeLength tests ID generation with a very large length.
func TestGenerateWithVeryLargeLength(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Define a standard alphabet
alphabet := "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
const idLength = 1000 // Very large length
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithLengthHint(idLength),
)
is.NoError(err, "NewGenerator() should not return an error with a valid alphabet")
id, err := gen.New(idLength)
is.NoError(err, "gen.New(%d) should not return an error", idLength)
is.Equal(idLength, len([]rune(id)), "Generated ID should have the specified length")
is.True(isValidID(id, alphabet), "Generated ID contains invalid characters")
}
// TestGeneratorBufferReuse tests that buffers are correctly reused from the pool without residual data.
func TestGeneratorBufferReuse(t *testing.T) {
t.Parallel()
is := assert.New(t)
alphabet := "XYZ123"
const idLength = 6
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithLengthHint(idLength),
)
is.NoError(err, "NewGenerator() should not return an error with a valid custom alphabet")
// Generate first ID
id1, err := gen.New(idLength)
is.NoError(err, "gen.New(%d) should not return an error", idLength)
is.Equal(idLength, len([]rune(id1.String())), "Generated ID should have the specified length")
is.True(isValidID(id1, alphabet), "Generated ID contains invalid characters")
// Generate second ID
id2, err := gen.New(idLength)
is.NoError(err, "gen.New(%d) should not return an error", idLength)
is.Equal(idLength, len([]rune(id2.String())), "Generated ID should have the specified length")
is.True(isValidID(id2, alphabet), "Generated ID contains invalid characters")
// Ensure that IDs are different if possible
if id1 == id2 {
t.Errorf("Generated IDs should be different: id1=%s, id2=%s", id1, id2)
}
}
// TestGenerateWithMaxAttempts tests that the generator returns ErrExceededMaxAttempts when it cannot generate enough valid characters.
func TestGenerateWithMaxAttempts(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Define a small alphabet
alphabet := "ABC" // len=3, bitsNeeded=2, mask=3
// Define a random reader that always returns rnd=3 (>= len(alphabet)=3)
failReader := &alwaysFailRandReader{}
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithRandReader(failReader),
WithLengthHint(10),
)
is.NoError(err, "NewGenerator() should not return an error with a valid custom alphabet and fail reader")
// Attempt to generate an ID
id, err := gen.New(10)
is.Error(err, "gen.New(10) should return an error when random reader cannot provide valid characters")
is.Empty(id, "Generated ID should be empty on error")
is.Equal(io.EOF, err, "Expected io.EOF")
}
// TestGeneratorWithZeroLengthHint tests the generator's behavior with LengthHint set to 0.
func TestGeneratorWithZeroLengthHint(t *testing.T) {
t.Parallel()
is := assert.New(t)
alphabet := "ABCDEFGHijklmnopQR"
lengthHint := uint16(0)
_, err := NewGenerator(
WithAlphabet(alphabet),
WithLengthHint(lengthHint),
)
is.Error(err, "NewGenerator() should return an error with LengthHint=0")
}
// TestNewWithZeroLengthHintAndMaxAlphabet tests the generator with LengthHint=0 and maximum alphabet size.
func TestNewWithZeroLengthHintAndMaxAlphabet(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Define the maximum valid alphabet size
alphabet := make([]rune, MaxAlphabetLength)
for i := 0; i < MaxAlphabetLength; i++ {
alphabet[i] = rune(i)
}
lengthHint := uint16(0)
gen, err := NewGenerator(
WithAlphabet(string(alphabet)),
WithLengthHint(lengthHint),
)
is.Error(err, "NewGenerator() should return an error with LengthHint=0 and maximum alphabet size")
is.Nil(gen, "Interface should be nil when LengthHint is zero")
}
// TestGenerateWithCustomRandReaderReturningNoBytes tests generator behavior when the custom reader returns no bytes.
func TestGenerateWithCustomRandReaderReturningNoBytes(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Define a custom random reader that always returns zero bytes read
emptyReader := &emptyRandReader{}
const idLength = 8
// Initialize the generator with a valid alphabet and the empty random reader
alphabet := "ABCDEFGH"
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithRandReader(emptyReader),
WithLengthHint(idLength),
)
is.NoError(err, "NewGenerator() should not return an error with a valid custom alphabet")
// Attempt to generate an ID
id, err := gen.New(idLength)
is.Error(err, "gen.New() should return an error when random reader provides no bytes")
is.Empty(id, "Generated ID should be empty on error")
is.Equal(io.EOF, err, "Expected io.EOF from emptyRandReader")
}
// emptyRandReader is a custom io.Reader that always returns zero bytes read.
type emptyRandReader struct{}
// Read implements the io.Reader interface and always returns 0 bytes read.
func (f *emptyRandReader) Read(_ []byte) (int, error) {
return 0, io.EOF
}
// TestGeneratorConcurrencyWithCustomAlphabetLength tests that the generator can handle concurrent ID generation with custom alphabet lengths.
func TestGeneratorConcurrencyWithCustomAlphabetLength(t *testing.T) {
t.Parallel()
is := assert.New(t)
numGoroutines := 50
numIDsPerGoroutine := 20
customAlphabet := "abcdefghijklmnopqrstuvwxyz0123456789"
idLength := 15
gen, err := NewGenerator(
WithAlphabet(customAlphabet),
WithLengthHint(uint16(idLength)),
)
is.NoError(err, "NewGenerator() should not return an error with a valid custom alphabet")
var wg sync.WaitGroup
wg.Add(numGoroutines)
ids := make(chan ID, numGoroutines*numIDsPerGoroutine)
errorsChan := make(chan error, numGoroutines*numIDsPerGoroutine)
for i := 0; i < numGoroutines; i++ {
go func() {
defer wg.Done()
for j := 0; j < numIDsPerGoroutine; j++ {
id, err := gen.New(idLength)
if err != nil {
errorsChan <- err
continue
}
ids <- id
}
}()
}
wg.Wait()
close(ids)
close(errorsChan)
for err := range errorsChan {
is.NoError(err, "gen.New() should not return an error in concurrent execution")
}
idSet := make(map[ID]struct{}, numGoroutines*numIDsPerGoroutine)
for id := range ids {
if _, exists := idSet[id]; exists {
is.Failf("Duplicate ID found in concurrency test", "Duplicate ID: %s", id)
}
idSet[id] = struct{}{}
}
}
// TestGenerateWithAllPrintableASCII tests the generation of IDs using all printable ASCII characters.
func TestGenerateWithAllPrintableASCII(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Define an alphabet with all printable ASCII characters
var alphabet string
for i := 32; i <= 126; i++ {
alphabet += string(rune(i))
}
const idLength = 20
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithLengthHint(idLength),
)
is.NoError(err, "NewGenerator() should not return an error with all printable ASCII characters")
id, err := gen.New(idLength)
is.NoError(err, "gen.New(%d) should not return an error", idLength)
is.Equal(idLength, len([]rune(id)), "Generated ID should have the specified length")
is.True(isValidID(id, alphabet), "Generated ID contains invalid characters")
}
// TestGenerateWithSpecialUTF8Characters tests the generation of IDs with an alphabet containing special UTF-8 characters.
func TestGenerateWithSpecialUTF8Characters(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Alphabet with special UTF-8 characters
alphabet := "äöüß😊✨💖"
const idLength = 15
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithLengthHint(idLength),
)
is.NoError(err, "NewGenerator() should not return an error with a special UTF-8 characters alphabet")
id, err := gen.New(idLength)
is.NoError(err, "gen.New(%d) should not return an error", idLength)
is.Equal(idLength, len([]rune(id)), "Generated ID should have the specified length")
is.True(isValidID(id, alphabet), "Generated ID contains invalid characters")
}
// TestGeneratorWithInvalidLengthHint tests that the generator returns an error when LengthHint is invalid.
func TestGeneratorWithInvalidLengthHint(t *testing.T) {
t.Parallel()
is := assert.New(t)
alphabet := "ABCDEFG"
lengthHint := uint16(0)
_, err := NewGenerator(
WithAlphabet(alphabet),
WithLengthHint(lengthHint),
)
is.Error(err, "NewGenerator() should return an error when LengthHint is zero")
is.Equal(ErrInvalidLength, err, "Expected ErrInvalidLength for LengthHint=0")
}
// TestGenerateWithMaxAttemptsExceeded tests the generator's behavior when it exceeds the maximum number of attempts.
func TestGenerateWithMaxAttemptsExceeded(t *testing.T) {
t.Parallel()
is := assert.New(t)
// Define a small alphabet
alphabet := "AB"
const idLength = 100
failReader := &alwaysFailRandReader{}
gen, err := NewGenerator(
WithAlphabet(alphabet),
WithRandReader(failReader),
WithLengthHint(idLength),
)
is.NoError(err, "NewGenerator() should not return an error with a valid small alphabet")
id, err := gen.New(idLength)
is.Error(err, "gen.New(%d) should return an error when random reader cannot provide valid characters", idLength)
is.Empty(id, "Generated ID should be empty on error")
is.Equal(io.EOF, err, "Expected io.EOF when maximum attempts are exceeded")
}
// alwaysFailRandReader is a custom io.Reader that always returns an error.
type alwaysFailRandReader struct{}
// Read implements the io.Reader interface and always returns an error.
func (f *alwaysFailRandReader) Read(p []byte) (int, error) {
for i := range p {
p[i] = 3 // Assuming len(customAlphabet)=2, rnd=3 >= 2
}
return len(p), io.EOF
}
// TestGenerateWithEmptyAlphabet tests the generator's behavior when an empty alphabet is provided.
func TestGenerateWithEmptyAlphabet(t *testing.T) {
t.Parallel()
is := assert.New(t)
alphabet := ""
_, err := NewGenerator(
WithAlphabet(alphabet),
)
is.Error(err, "NewGenerator() should return an error when alphabet is empty")
is.Equal(ErrInvalidAlphabet, err, "Expected ErrInvalidAlphabet when the alphabet is empty")
}
// TestGenerateWithNilRandReader tests the generator's behavior when a nil random reader is provided.
func TestGenerateWithNilRandReader(t *testing.T) {
t.Parallel()
is := assert.New(t)
alphabet := "ABCDEFG"
_, err := NewGenerator(
WithAlphabet(alphabet),
WithRandReader(io.Reader(nil)),
)
is.Error(err, "NewGenerator() should return an error when RandReader is nil")
}
// TestProcessRandomBytes tests the processRandomBytes function to ensure coverage for different cases.
func TestProcessRandomBytes(t *testing.T) {
is := assert.New(t)
gen, err := NewGenerator()
is.NoError(err, "NewGenerator() should not return an error with default configuration")
randomBytes := []byte{0x12, 0x34, 0x56, 0x78, 0x9A, 0xBC}
// Case 1: bytesNeeded = 1
gen.(*generator).config.bytesNeeded = 1
result := gen.(*generator).processRandomBytes(randomBytes, 0)
is.Equal(uint(0x12), result, "Expected result to be 0x12 for bytesNeeded=1")
// Case 2: bytesNeeded = 2
gen.(*generator).config.bytesNeeded = 2
result = gen.(*generator).processRandomBytes(randomBytes, 0)
is.Equal(uint(0x1234), result, "Expected result to be 0x1234 for bytesNeeded=2")
// Case 3: bytesNeeded = 4
gen.(*generator).config.bytesNeeded = 4
result = gen.(*generator).processRandomBytes(randomBytes, 0)
is.Equal(uint(0x12345678), result, "Expected result to be 0x12345678 for bytesNeeded=4")
// Case 4: bytesNeeded > 4 (default case)
gen.(*generator).config.bytesNeeded = 6
result = gen.(*generator).processRandomBytes(randomBytes, 0)
is.Equal(uint(0x123456789ABC), result, "Expected result to be 0x123456789ABC for bytesNeeded=6")
}
// TestGenerator_Read_EqualLength tests reading into a buffer equal to the default ID length.
func TestGenerator_Read_EqualLength(t *testing.T) {
t.Parallel()
is := assert.New(t)
buffer := make([]byte, DefaultLength)
n, err := Read(buffer)
is.NoError(err, "Read should not return an error")
is.Equal(DefaultLength, n, "Number of bytes read should equal DefaultLength")
id := ID(buffer)
is.Equal(DefaultLength, len(id), "Generated ID length should match DefaultLength")
is.True(isValidID(id, DefaultAlphabet), "Generated ID should contain only valid characters")
}
// TestGenerator_Read_SmallerBuffer tests reading into a buffer smaller than the default ID length.
func TestGenerator_Read_SmallerBuffer(t *testing.T) {
t.Parallel()
is := assert.New(t)
const length = 10
gen, err := NewGenerator(WithLengthHint(length))
is.NoError(err, "NewGenerator() should not return an error with length hint 10")
buffer := make([]byte, length)
n, err := gen.Read(buffer)
is.NoError(err, "Read should not return an error")
is.Equal(length, n, "Number of bytes read should equal bufferSize")
id := ID(buffer)
is.Equal(length, len(id), "Generated ID length should match bufferSize")
is.True(isValidID(id, DefaultAlphabet), "Generated ID should contain only valid characters")
}
// TestGenerator_Read_LargerBuffer tests reading into a buffer larger than the default ID length.
func TestGenerator_Read_LargerBuffer(t *testing.T) {
t.Parallel()
is := assert.New(t)
const length = 10
gen, err := NewGenerator(WithLengthHint(length))
is.NoError(err, "NewGenerator() should not return an error with length hint 10")
buffer := make([]byte, length)
n, err := gen.Read(buffer)
is.NoError(err, "Read should not return an error")
is.Equal(length, n, "Number of bytes read should equal bufferSize")
id := ID(buffer)
is.Equal(length, len(id), "Generated ID length should match bufferSize")
is.True(isValidID(id, DefaultAlphabet), "Generated ID should contain only valid characters")
}
// TestGenerator_Read_ZeroBuffer tests reading into a zero-length buffer.
func TestGenerator_Read_ZeroBuffer(t *testing.T) {
t.Parallel()
is := assert.New(t)
gen, err := NewGenerator()
is.NoError(err, "NewGenerator() should not return an error with length hint 10")
buffer := make([]byte, 0)
n, err := gen.Read(buffer)
is.NoError(err, "Read should not return an error")
is.Equal(0, n, "Number of bytes read should be 0 for zero-length buffer")
}
// TestGenerator_Read_Concurrent tests concurrent reads to ensure thread safety.
func TestGenerator_Read_Concurrent(t *testing.T) {
t.Parallel()
is := assert.New(t)
gen, ok := Generator.(*generator)
is.True(ok, "Generator should be of type *generator")
numGoroutines := 10
readsPerGoroutine := 100
bufferSize := DefaultLength
var wg sync.WaitGroup
var mu sync.Mutex
generatedIDs := make(map[ID]bool)
for i := 0; i < numGoroutines; i++ {
wg.Add(1)
go func() {
defer wg.Done()
for j := 0; j < readsPerGoroutine; j++ {
buffer := make([]byte, bufferSize)
n, err := gen.Read(buffer)
if !is.NoError(err, "Read should not return an error") {
return
}
is.Equal(bufferSize, n, "Number of bytes read should equal bufferSize")
id := ID(buffer)
is.Equal(bufferSize, len(id), "Generated ID length should match bufferSize")