golang.org/x/text v0.37.0: cases.Title, cases.Upper, cases.Lower

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 pkg:golang/golang.org/x/text@v0.37.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/text@v0.37.0

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:sha256:2ff11dd39a3f4e1523b6c46ec70ad00809e2b4a5a7f712567c22304d0dbc1201","contract":["cases.Title with English language tag capitalizes words","cases.Upper with Turkish language tag transforms lowercase 'i' to dotted capital 'İ'","cases.Lower with Turkish language tag transforms uppercase 'I' to dotless lowercase 'ı'","cases.Lower with English language tag converts uppercase to lowercase","language.Make produces canonical language tags"],"goal":"verify pkg:golang/golang.org/x/text@v0.37.0","kind":"HOW","packages":["pkg:golang/golang.org/x/text@v0.37.0"],"schemaVersion":1,"symbols":["golang.org/x/text/cases.Title","golang.org/x/text/cases.Upper","golang.org/x/text/cases.Lower","golang.org/x/text/language.Make"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","ecosystem":"golang","os":"windows","osVersionBucket":"11","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/golang.org/x/text@v0.37.0"],"schemaVersion":1,"symbols":["golang.org/x/text/cases.Title","golang.org/x/text/cases.Upper","golang.org/x/text/cases.Lower","golang.org/x/text/language.Make"],"verifierAdapter":"golang@1"}

module sample

go 1.25.0

require golang.org/x/text v0.37.0

golang.org/x/text v0.37.0 h1:Cqjiwd9eSg8e0QAkyCaQTNHFIIzWtidPahFWR83rTrc=
golang.org/x/text v0.37.0/go.mod h1:a5sjxXGs9hsn/AJVwuElvCAo9v8QYLzvavO5z2PiM38=

package main

import (
	"fmt"

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

func main() {
	enTitle := cases.Title(language.English)
	fmt.Println("English Title:", enTitle.String("the quick brown fox"))

	trUpper := cases.Upper(language.Turkish)
	fmt.Println("Turkish Upper of 'i':", trUpper.String("i"))

	enLower := cases.Lower(language.English)
	fmt.Println("English Lower:", enLower.String("HELLO WORLD"))
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/golang.org/x/text@v0.37.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/text@v0.37.0"
  ]
}

package main

import (
	"fmt"
	"os"

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

func main() {
	// Assertion 1: cases.Title with English language tag capitalizes words
	enTitle := cases.Title(language.English)
	gotTitle := enTitle.String("the quick brown fox")
	expectedTitle := "The Quick Brown Fox"
	if gotTitle != expectedTitle {
		fmt.Fprintf(os.Stderr, "FAIL: cases.Title(English) got %q, want %q\n", gotTitle, expectedTitle)
		os.Exit(1)
	}

	// Assertion 2: cases.Upper with Turkish language tag transforms lowercase 'i' to dotted capital 'İ'
	trUpper := cases.Upper(language.Turkish)
	gotTrUpper := trUpper.String("i")
	expectedTrUpper := "\u0130" // "İ"
	if gotTrUpper != expectedTrUpper {
		fmt.Fprintf(os.Stderr, "FAIL: cases.Upper(Turkish) for 'i' got %q, want %q\n", gotTrUpper, expectedTrUpper)
		os.Exit(1)
	}

	// Assertion 3: cases.Lower with Turkish language tag transforms uppercase 'I' to dotless lowercase 'ı'
	trLower := cases.Lower(language.Turkish)
	gotTrLower := trLower.String("I")
	expectedTrLower := "\u0131" // "ı"
	if gotTrLower != expectedTrLower {
		fmt.Fprintf(os.Stderr, "FAIL: cases.Lower(Turkish) for 'I' got %q, want %q\n", gotTrLower, expectedTrLower)
		os.Exit(1)
	}

	// Assertion 4: cases.Lower with English language tag converts uppercase to lowercase
	enLower := cases.Lower(language.English)
	gotLower := enLower.String("HELLO WORLD")
	expectedLower := "hello world"
	if gotLower != expectedLower {
		fmt.Fprintf(os.Stderr, "FAIL: cases.Lower(English) got %q, want %q\n", gotLower, expectedLower)
		os.Exit(1)
	}

	// Assertion 5: language.Make produces canonical language tags
	tag := language.Make("en-US")
	if tag.String() != "en-US" {
		fmt.Fprintf(os.Stderr, "FAIL: language.Make got %q, want %q\n", tag.String(), "en-US")
		os.Exit(1)
	}

	fmt.Println("PASS: all contract assertions passed for pkg:golang/golang.org/x/text@v0.37.0")
}