golang.org/x/text v0.3.2: 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 cases.Title in pkg:golang/golang.org/x/text@v0.3.2
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/text@v0.3.2
Demonstrate these symbols/APIs:
  - 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.

package textcases

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

// Titlecase converts a string to title case using the specified language tag and options.
func Titlecase(tag language.Tag, s string, opts ...cases.Option) string {
	return cases.Title(tag, opts...).String(s)
}

// TitlecaseBytes converts a byte slice to title case using the specified language tag and options.
func TitlecaseBytes(tag language.Tag, b []byte, opts ...cases.Option) []byte {
	return cases.Title(tag, opts...).Bytes(b)
}

{"case":{"caseId":"case:sha256:5d7b2291e4445c3fdeb838d8eaaf1b7f6fb1e5b0456cae125ab7f97c7fcdb0d9","contract":["cases.Title converts strings and byte slices to title case according to language rules","cases.NoLower preserves existing uppercase in non-initial positions","cases.Title handles language-specific title casing for Turkish dotted I and Dutch IJ"],"goal":"verify cases.Title in pkg:golang/golang.org/x/text@v0.3.2","kind":"HOW","packages":["pkg:golang/golang.org/x/text@v0.3.2"],"schemaVersion":1,"symbols":["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@v0.3.2"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/text@v0.3.2","symbols":["cases.Title"],"verifierAdapter":"golang@1"}

module example.com/cases-sample

go 1.26.6

require golang.org/x/text v0.3.2

golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

{
  "schemaVersion": 1,
  "goal": "verify cases.Title in pkg:golang/golang.org/x/text@v0.3.2",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/text@v0.3.2"
  ],
  "symbols": [
    "cases.Title"
  ]
}

package main

import (
	"bytes"
	"fmt"
	"os"

	textcases "example.com/cases-sample"
	"golang.org/x/text/cases"
	"golang.org/x/text/language"
)

func main() {
	// Assertion 1: Basic title casing with language.Und
	undCaser := cases.Title(language.Und)
	if got := undCaser.String("hello world"); got != "Hello World" {
		fmt.Fprintf(os.Stderr, "FAIL: expected 'Hello World', got %q\n", got)
		os.Exit(1)
	}
	if got := undCaser.String("HELLO WORLD"); got != "Hello World" {
		fmt.Fprintf(os.Stderr, "FAIL: expected 'Hello World', got %q\n", got)
		os.Exit(1)
	}

	// Assertion 2: Byte slice transformation with Bytes()
	inputBytes := []byte("data stream")
	expectedBytes := []byte("Data Stream")
	if got := undCaser.Bytes(inputBytes); !bytes.Equal(got, expectedBytes) {
		fmt.Fprintf(os.Stderr, "FAIL: expected %q, got %q\n", expectedBytes, got)
		os.Exit(1)
	}

	// Assertion 3: NoLower option preserves existing uppercase non-initial letters
	noLowerCaser := cases.Title(language.Und, cases.NoLower)
	if got := noLowerCaser.String("hELLO wORLD"); got != "HELLO WORLD" {
		fmt.Fprintf(os.Stderr, "FAIL: expected 'HELLO WORLD', got %q\n", got)
		os.Exit(1)
	}

	// Assertion 4: Turkish language title casing (dotted and dotless I)
	// 'i' (U+0069) -> 'İ' (U+0130, Latin capital letter I with dot above)
	// 'ı' (U+0131) -> 'I' (U+0049, Latin capital letter I)
	trCaser := cases.Title(language.Turkish)
	if got := trCaser.String("istanbul"); got != "İstanbul" {
		fmt.Fprintf(os.Stderr, "FAIL: Turkish 'istanbul' expected 'İstanbul', got %q\n", got)
		os.Exit(1)
	}
	if got := trCaser.String("ılık"); got != "Ilık" {
		fmt.Fprintf(os.Stderr, "FAIL: Turkish 'ılık' expected 'Ilık', got %q\n", got)
		os.Exit(1)
	}

	// Assertion 5: Dutch language title casing (capitalizes 'ij' digraph as 'IJ')
	nlCaser := cases.Title(language.Dutch)
	if got := nlCaser.String("ijsland"); got != "IJsland" {
		fmt.Fprintf(os.Stderr, "FAIL: Dutch 'ijsland' expected 'IJsland', got %q\n", got)
		os.Exit(1)
	}

	// Assertion 6: Helper functions Titlecase and TitlecaseBytes
	if got := textcases.Titlecase(language.English, "go programming"); got != "Go Programming" {
		fmt.Fprintf(os.Stderr, "FAIL: helper Titlecase expected 'Go Programming', got %q\n", got)
		os.Exit(1)
	}
	if got := textcases.TitlecaseBytes(language.English, []byte("gopher")); !bytes.Equal(got, []byte("Gopher")) {
		fmt.Fprintf(os.Stderr, "FAIL: helper TitlecaseBytes expected 'Gopher', got %q\n", got)
		os.Exit(1)
	}

	fmt.Println("PASS: cases.Title contract passed")
}