github.com/rs/xid v1.5.0: generate xid, encode to string, parse from string, extract timestamp and bytes

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: generate xid, encode to string, parse from string, extract timestamp and bytes
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/rs/xid@v1.5.0
Demonstrate these symbols/APIs:
  - github.com/rs/xid.FromBytes
  - github.com/rs/xid.FromString
  - github.com/rs/xid.ID.Bytes
  - github.com/rs/xid.ID.String
  - github.com/rs/xid.ID.Time
  - github.com/rs/xid.New
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:1ee2074f06efe6631b7b33762c25705ffbb86fdfa1065566d701692e1cf68898","contract":["xid.New generates a non-nil 12-byte identifier with the current unix timestamp","id.String returns a 20-character base32 lowercase representation of the identifier","xid.FromString parses a valid 20-character string back to the equal xid.ID and rejects invalid format or length","id.Bytes returns a 12-byte slice representation of the identifier","xid.FromBytes parses a 12-byte slice back to the equal xid.ID and rejects slices of length other than 12","id.Time extracts the embedded timestamp from the identifier truncated to seconds"],"goal":"generate xid, encode to string, parse from string, extract timestamp and bytes","kind":"HOW","packages":["pkg:golang/github.com/rs/xid@v1.5.0"],"schemaVersion":1,"symbols":["github.com/rs/xid.FromBytes","github.com/rs/xid.FromString","github.com/rs/xid.ID.Bytes","github.com/rs/xid.ID.String","github.com/rs/xid.ID.Time","github.com/rs/xid.New"]},"contractCommand":["go","test","./..."],"environment":{"arch":"x64","compiler":"go","compilerVersion":"1.26.6","distro":"ubuntu","ecosystem":"golang","language":"go","languageVersion":"1.26.6","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/rs/xid@v1.5.0"],"schemaVersion":1,"subject":"pkg:golang/github.com/rs/xid@v1.5.0","symbols":["github.com/rs/xid.FromBytes","github.com/rs/xid.FromString","github.com/rs/xid.ID.Bytes","github.com/rs/xid.ID.String","github.com/rs/xid.ID.Time","github.com/rs/xid.New"],"verifierAdapter":"golang@1"}

module example.com/xid-sample

go 1.22

require github.com/rs/xid v1.5.0

github.com/rs/xid v1.5.0 h1:mKX4bl4iPYJtEIxp6CYiUuLQ/8DYMoz0PUdtGgMFRVc=
github.com/rs/xid v1.5.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=

{
  "schemaVersion": 1,
  "goal": "generate xid, encode to string, parse from string, extract timestamp and bytes",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/rs/xid@v1.5.0"
  ],
  "symbols": [
    "github.com/rs/xid.FromBytes",
    "github.com/rs/xid.FromString",
    "github.com/rs/xid.ID.Bytes",
    "github.com/rs/xid.ID.String",
    "github.com/rs/xid.ID.Time",
    "github.com/rs/xid.New"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

package test

import (
	"bytes"
	"testing"
	"time"

	"github.com/rs/xid"
)

func TestXIDGenerationAndString(t *testing.T) {
	before := time.Now().Truncate(time.Second)
	id := xid.New()
	after := time.Now().Add(time.Second).Truncate(time.Second)

	if id.IsNil() {
		t.Fatal("expected non-nil xid")
	}

	str := id.String()
	if len(str) != 20 {
		t.Fatalf("expected string length 20, got %d: %q", len(str), str)
	}

	parsed, err := xid.FromString(str)
	if err != nil {
		t.Fatalf("xid.FromString failed: %v", err)
	}
	if parsed != id {
		t.Fatalf("parsed id %v does not match original %v", parsed, id)
	}

	// Test invalid string parsing
	if _, err := xid.FromString("invalid-xid-string"); err == nil {
		t.Fatal("expected error parsing invalid string, got nil")
	}
	if _, err := xid.FromString("short"); err == nil {
		t.Fatal("expected error parsing short string, got nil")
	}

	// Test timestamp extraction
	ts := id.Time()
	if ts.Before(before.Add(-time.Second)) || ts.After(after.Add(time.Second)) {
		t.Fatalf("id.Time() %v not within expected range [%v, %v]", ts, before, after)
	}
}

func TestXIDBinaryRepresentation(t *testing.T) {
	id := xid.New()
	rawBytes := id.Bytes()

	if len(rawBytes) != 12 {
		t.Fatalf("expected 12 bytes, got %d", len(rawBytes))
	}

	parsed, err := xid.FromBytes(rawBytes)
	if err != nil {
		t.Fatalf("xid.FromBytes failed: %v", err)
	}
	if parsed != id {
		t.Fatalf("parsed id %v from bytes does not match original %v", parsed, id)
	}

	if !bytes.Equal(parsed.Bytes(), rawBytes) {
		t.Fatalf("re-serialized bytes %v do not match original bytes %v", parsed.Bytes(), rawBytes)
	}

	// Test invalid bytes parsing
	if _, err := xid.FromBytes([]byte{1, 2, 3}); err == nil {
		t.Fatal("expected error for byte slice of length < 12")
	}
	if _, err := xid.FromBytes(make([]byte, 13)); err == nil {
		t.Fatal("expected error for byte slice of length > 12")
	}
}