golang.org/x/text v0.16.0: cases.Title

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: verify golang.org/x/text/cases.Title in pkg:golang/golang.org/x/text@v0.16.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/text@v0.16.0
Demonstrate these symbols/APIs:
  - golang.org/x/text/cases.Title

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:sha256:7a9ee9304bca8f7c6a819a73d3d24483e67130c7440bf91dbaa679cc1143d6a6","contract":["cases.Title with language.English converts lower case words to title case","cases.Title with language.English lowers uppercase characters not at word start by default","cases.Title with cases.NoLower preserves existing uppercase characters not at word start","cases.Title with language.Dutch capitalizes ij digraph at word start as IJ","cases.Title with language.Und returns empty string for empty input","cases.Title Bytes method transforms byte slice to title case"],"goal":"verify golang.org/x/text/cases.Title in pkg:golang/golang.org/x/text@v0.16.0","kind":"HOW","packages":["pkg:golang/golang.org/x/text@v0.16.0"],"schemaVersion":1,"symbols":["golang.org/x/text/cases.Title"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/golang.org/x/text@v0.16.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/text@v0.16.0","symbols":["golang.org/x/text/cases.Title"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.23

require golang.org/x/text v0.16.0

golang.org/x/text v0.16.0 h1:a94ExnEXNtEwYLGJSIUxnWoxoRz/ZcCsV63ROupILh4=
golang.org/x/text v0.16.0/go.mod h1:GhwF1Be+LQoKShO3cGOHzqOgRrGaYc9AvblQOmPVHnI=

package main

import (
	"fmt"

	"golang.org/x/text/cases"
	"golang.org/x/text/language"
)

func main() {
	enTitle := cases.Title(language.English)
	fmt.Println(enTitle.String("hello world"))

	dutchTitle := cases.Title(language.Dutch)
	fmt.Println(dutchTitle.String("ijsland"))

	noLowerTitle := cases.Title(language.English, cases.NoLower)
	fmt.Println(noLowerTitle.String("iPad"))
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/text/cases.Title in pkg:golang/golang.org/x/text@v0.16.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/text@v0.16.0"
  ],
  "symbols": [
    "golang.org/x/text/cases.Title"
  ]
}

package main

import (
	"bytes"
	"fmt"
	"os"

	"golang.org/x/text/cases"
	"golang.org/x/text/language"
)

func main() {
	// 1. cases.Title with language.English converts lower case words to title case
	got1 := cases.Title(language.English).String("the quick brown fox")
	expected1 := "The Quick Brown Fox"
	if got1 != expected1 {
		fmt.Fprintf(os.Stderr, "assertion 1 failed: expected %q, got %q\n", expected1, got1)
		os.Exit(1)
	}

	// 2. cases.Title with language.English lowers uppercase characters not at word start by default
	got2 := cases.Title(language.English).String("HELLO WORLD")
	expected2 := "Hello World"
	if got2 != expected2 {
		fmt.Fprintf(os.Stderr, "assertion 2 failed: expected %q, got %q\n", expected2, got2)
		os.Exit(1)
	}

	// 3. cases.Title with cases.NoLower preserves existing uppercase characters not at word start
	got3 := cases.Title(language.English, cases.NoLower).String("HELLO WORLD")
	expected3 := "HELLO WORLD"
	if got3 != expected3 {
		fmt.Fprintf(os.Stderr, "assertion 3 failed: expected %q, got %q\n", expected3, got3)
		os.Exit(1)
	}

	// 4. cases.Title with language.Dutch capitalizes ij digraph at word start as IJ
	got4 := cases.Title(language.Dutch).String("ijsland")
	expected4 := "IJsland"
	if got4 != expected4 {
		fmt.Fprintf(os.Stderr, "assertion 4 failed: expected %q, got %q\n", expected4, got4)
		os.Exit(1)
	}

	// 5. cases.Title with language.Und returns empty string for empty input
	got5 := cases.Title(language.Und).String("")
	expected5 := ""
	if got5 != expected5 {
		fmt.Fprintf(os.Stderr, "assertion 5 failed: expected %q, got %q\n", expected5, got5)
		os.Exit(1)
	}

	// 6. cases.Title Bytes method transforms byte slice to title case
	got6 := cases.Title(language.Und).Bytes([]byte("golang"))
	expected6 := []byte("Golang")
	if !bytes.Equal(got6, expected6) {
		fmt.Fprintf(os.Stderr, "assertion 6 failed: expected %q, got %q\n", expected6, got6)
		os.Exit(1)
	}

	fmt.Println("All contract assertions passed.")
}