golang.org/x/net v0.0.0-20210525063256-abc453219eb5: atom.String

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/net/html/atom.String in pkg:golang/golang.org/x/net@v0.0.0-20210525063256-abc453219eb5
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/net@v0.0.0-20210525063256-abc453219eb5
Demonstrate these symbols/APIs:
  - golang.org/x/net/html/atom.String

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:sha256:943591ec07bd618296c274d2e17762e8f516ae7aebcc5cd04b8632b267c993e4","contract":["atom.String converts byte slices of known HTML atoms to their canonical string representations","atom.String returns the string value for byte slices not present in the atom table","Atom.String returns the tag name for valid atoms and empty string for the zero atom"],"goal":"verify golang.org/x/net/html/atom.String in pkg:golang/golang.org/x/net@v0.0.0-20210525063256-abc453219eb5","kind":"HOW","packages":["pkg:golang/golang.org/x/net@v0.0.0-20210525063256-abc453219eb5"],"schemaVersion":1,"symbols":["golang.org/x/net/html/atom.String"]},"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/net@v0.0.0-20210525063256-abc453219eb5"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/net@v0.0.0-20210525063256-abc453219eb5","symbols":["golang.org/x/net/html/atom.String"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26

require golang.org/x/net v0.0.0-20210525063256-abc453219eb5

golang.org/x/net v0.0.0-20210525063256-abc453219eb5 h1:wjuX4b5yYQnEQHzd+CBcrcC6OVR2J1CN6mUy0oSxIPo=
golang.org/x/net v0.0.0-20210525063256-abc453219eb5/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=

package main

import (
	"fmt"

	"golang.org/x/net/html/atom"
)

func main() {
	known := []byte("div")
	fmt.Printf("atom.String(%q) = %q\n", string(known), atom.String(known))

	unknown := []byte("custom-widget")
	fmt.Printf("atom.String(%q) = %q\n", string(unknown), atom.String(unknown))

	fmt.Printf("atom.Div.String() = %q\n", atom.Div.String())
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/net/html/atom.String in pkg:golang/golang.org/x/net@v0.0.0-20210525063256-abc453219eb5",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/net@v0.0.0-20210525063256-abc453219eb5"
  ],
  "symbols": [
    "golang.org/x/net/html/atom.String"
  ]
}

package main

import (
	"fmt"
	"os"

	"golang.org/x/net/html/atom"
)

func main() {
	if err := verifyAtomString(); err != nil {
		fmt.Fprintf(os.Stderr, "contract failed: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("contract passed")
}

func verifyAtomString() error {
	// 1. atom.String converts byte slices of known HTML atoms to their canonical string representations
	knownCases := []struct {
		text string
		code atom.Atom
	}{
		{"a", atom.A},
		{"div", atom.Div},
		{"span", atom.Span},
		{"p", atom.P},
		{"table", atom.Table},
		{"body", atom.Body},
		{"html", atom.Html},
	}
	for _, tc := range knownCases {
		got := atom.String([]byte(tc.text))
		if got != tc.text {
			return fmt.Errorf("atom.String(%q) = %q, want %q", tc.text, got, tc.text)
		}
		if got != tc.code.String() {
			return fmt.Errorf("atom.String(%q) = %q, want %q from Atom.String()", tc.text, got, tc.code.String())
		}
	}

	// 2. atom.String returns the string value for byte slices not present in the atom table
	unknownCases := []string{
		"custom-element",
		"nonexistent-tag",
		"x-widget-123",
	}
	for _, s := range unknownCases {
		if code := atom.Lookup([]byte(s)); code != 0 {
			return fmt.Errorf("atom.Lookup(%q) = %v, want 0", s, code)
		}
		if got := atom.String([]byte(s)); got != s {
			return fmt.Errorf("atom.String(%q) = %q, want %q", s, got, s)
		}
	}

	// 3. Atom.String returns the tag name for valid atoms and empty string for the zero atom
	if got := atom.Atom(0).String(); got != "" {
		return fmt.Errorf("atom.Atom(0).String() = %q, want empty string", got)
	}
	if got := atom.String([]byte{}); got != "" {
		return fmt.Errorf("atom.String([]byte{}) = %q, want empty string", got)
	}

	return nil
}