golang.org/x/net v0.0.0-20200226121028-0de0cce0169b: atom.Lookup

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.Lookup in pkg:golang/golang.org/x/net@v0.0.0-20200226121028-0de0cce0169b
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/net@v0.0.0-20200226121028-0de0cce0169b
Demonstrate these symbols/APIs:
  - golang.org/x/net/html/atom.Lookup

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:db698bf0e97e0f0385950066bdaa5a29b6344e828c1c5486c4da596af47f1206","contract":["atom.Lookup resolves known tag \"div\" to atom.Div","atom.Lookup resolves known tag \"a\" to atom.A","atom.Lookup returns 0 for unknown tag names","atom.Lookup is case-sensitive and returns 0 for uppercase tag names","sample.LookupAtomString resolves \"span\" to atom.Span","sample.IsKnownAtom returns true for valid atoms and false for unknown tags"],"goal":"verify golang.org/x/net/html/atom.Lookup in pkg:golang/golang.org/x/net@v0.0.0-20200226121028-0de0cce0169b","kind":"HOW","packages":["pkg:golang/golang.org/x/net@v0.0.0-20200226121028-0de0cce0169b"],"schemaVersion":1,"symbols":["golang.org/x/net/html/atom.Lookup"]},"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@v0.0.0-20200226121028-0de0cce0169b"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/net@v0.0.0-20200226121028-0de0cce0169b","symbols":["golang.org/x/net/html/atom.Lookup"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.21

require golang.org/x/net v0.0.0-20200226121028-0de0cce0169b

golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
golang.org/x/net v0.0.0-20200226121028-0de0cce0169b h1:0mm1VjtFUOIlE1SbDlwjYaDxZVDP2S5ou6y0gSgXHu8=
golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

package sample

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

// LookupAtom resolves a lowercase HTML tag byte slice to its atom.Atom value.
func LookupAtom(tag []byte) atom.Atom {
	return atom.Lookup(tag)
}

// LookupAtomString resolves a lowercase HTML tag string to its atom.Atom value.
func LookupAtomString(tag string) atom.Atom {
	return atom.Lookup([]byte(tag))
}

// IsKnownAtom reports whether the given byte slice maps to a known HTML atom.
func IsKnownAtom(tag []byte) bool {
	return atom.Lookup(tag) != 0
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/net/html/atom.Lookup in pkg:golang/golang.org/x/net@v0.0.0-20200226121028-0de0cce0169b",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/net@v0.0.0-20200226121028-0de0cce0169b"
  ],
  "symbols": [
    "golang.org/x/net/html/atom.Lookup"
  ]
}

package main

import (
	"fmt"
	"os"

	"example.com/sample"
	"golang.org/x/net/html/atom"
)

func main() {
	// 1. atom.Lookup resolves known tag "div" to atom.Div
	if got := atom.Lookup([]byte("div")); got != atom.Div {
		fmt.Fprintf(os.Stderr, "expected atom.Lookup(\"div\") == atom.Div, got %v\n", got)
		os.Exit(1)
	}

	// 2. atom.Lookup resolves known tag "a" to atom.A
	if got := atom.Lookup([]byte("a")); got != atom.A {
		fmt.Fprintf(os.Stderr, "expected atom.Lookup(\"a\") == atom.A, got %v\n", got)
		os.Exit(1)
	}

	// 3. atom.Lookup returns 0 for unknown tag names
	if got := atom.Lookup([]byte("nonexistent-tag")); got != 0 {
		fmt.Fprintf(os.Stderr, "expected atom.Lookup(\"nonexistent-tag\") == 0, got %v\n", got)
		os.Exit(1)
	}

	// 4. atom.Lookup is case-sensitive and returns 0 for uppercase tag names
	if got := atom.Lookup([]byte("DIV")); got != 0 {
		fmt.Fprintf(os.Stderr, "expected atom.Lookup(\"DIV\") == 0, got %v\n", got)
		os.Exit(1)
	}

	// 5. sample.LookupAtomString resolves "span" to atom.Span
	if got := sample.LookupAtomString("span"); got != atom.Span {
		fmt.Fprintf(os.Stderr, "expected sample.LookupAtomString(\"span\") == atom.Span, got %v\n", got)
		os.Exit(1)
	}

	// 6. sample.IsKnownAtom returns true for valid atoms and false for unknown tags
	if !sample.IsKnownAtom([]byte("body")) {
		fmt.Fprintf(os.Stderr, "expected sample.IsKnownAtom(\"body\") to be true\n")
		os.Exit(1)
	}
	if sample.IsKnownAtom([]byte("unknown-element")) {
		fmt.Fprintf(os.Stderr, "expected sample.IsKnownAtom(\"unknown-element\") to be false\n")
		os.Exit(1)
	}

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