golang.org/x/net v0.51.0: html.TokenType

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.TokenType in pkg:golang/golang.org/x/net@v0.51.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/net@v0.51.0
Demonstrate these symbols/APIs:
  - golang.org/x/net/html.TokenType

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:d8c27e7831be56d7f4584f5dcd514a2cf4b50e911ed667a99be1ed3e3165d3dd","contract":["TokenType String method returns expected string representation for all standard token types","html.NewTokenizer Next method parses HTML and produces expected TokenType sequence","SelfClosingTagToken is returned when tokenizer encounters self-closing void elements","CommentToken and DoctypeToken are correctly identified by tokenizer","ErrorToken is returned at end of input with io.EOF error"],"goal":"verify golang.org/x/net/html.TokenType in pkg:golang/golang.org/x/net@v0.51.0","kind":"HOW","packages":["pkg:golang/golang.org/x/net@v0.51.0"],"schemaVersion":1,"symbols":["golang.org/x/net/html.TokenType"]},"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@v0.51.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/net@v0.51.0","symbols":["golang.org/x/net/html.TokenType"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require golang.org/x/net v0.51.0

golang.org/x/net v0.51.0 h1:94R/GTO7mt3/4wIKpcR5gkGmRLOuE/2hNGeWq/GBIFo=
golang.org/x/net v0.51.0/go.mod h1:aamm+2QF5ogm02fjy5Bb7CQ0WMt1/WVM7FtyaTLlA9Y=

package main

import (
	"fmt"
	"io"
	"strings"

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

func main() {
	rawHTML := `<!DOCTYPE html><html><body><!-- comment --><p>Hello</p><br/></body></html>`
	z := html.NewTokenizer(strings.NewReader(rawHTML))

	for {
		tt := z.Next()
		if tt == html.ErrorToken {
			err := z.Err()
			if err == io.EOF {
				fmt.Println("End of tokens")
				break
			}
			fmt.Printf("Error: %v\n", err)
			break
		}
		fmt.Printf("Token: %s -> %s\n", tt.String(), z.Token().Data)
	}
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/net/html.TokenType in pkg:golang/golang.org/x/net@v0.51.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/net@v0.51.0"
  ],
  "symbols": [
    "golang.org/x/net/html.TokenType"
  ]
}

package main

import (
	"fmt"
	"io"
	"os"
	"strings"

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

func main() {
	// Assertion 1: TokenType String method returns expected string representation for all standard token types
	expectedStrings := map[html.TokenType]string{
		html.ErrorToken:          "Error",
		html.TextToken:           "Text",
		html.StartTagToken:       "StartTag",
		html.EndTagToken:         "EndTag",
		html.SelfClosingTagToken: "SelfClosingTag",
		html.CommentToken:        "Comment",
		html.DoctypeToken:        "Doctype",
	}

	for tt, expected := range expectedStrings {
		if tt.String() != expected {
			fmt.Fprintf(os.Stderr, "assertion failed: expected TokenType(%d).String() == %q, got %q\n", tt, expected, tt.String())
			os.Exit(1)
		}
	}

	// Assertion 2: html.NewTokenizer Next method parses HTML and produces expected TokenType sequence
	rawHTML := `<!DOCTYPE html><html><body><!-- sample comment --><p>Sample Text</p><img src="example.png"/></body></html>`
	z := html.NewTokenizer(strings.NewReader(rawHTML))

	expectedTokens := []struct {
		tokenType html.TokenType
		data      string
	}{
		{html.DoctypeToken, "html"},
		{html.StartTagToken, "html"},
		{html.StartTagToken, "body"},
		{html.CommentToken, " sample comment "},
		{html.StartTagToken, "p"},
		{html.TextToken, "Sample Text"},
		{html.EndTagToken, "p"},
		{html.SelfClosingTagToken, "img"},
		{html.EndTagToken, "body"},
		{html.EndTagToken, "html"},
	}

	for i, exp := range expectedTokens {
		tt := z.Next()
		if tt != exp.tokenType {
			fmt.Fprintf(os.Stderr, "assertion failed at index %d: expected TokenType %s, got %s\n", i, exp.tokenType.String(), tt.String())
			os.Exit(1)
		}
		tok := z.Token()
		if tok.Type != exp.tokenType {
			fmt.Fprintf(os.Stderr, "assertion failed at index %d: expected Token.Type %s, got %s\n", i, exp.tokenType.String(), tok.Type.String())
			os.Exit(1)
		}
		if tok.Data != exp.data {
			fmt.Fprintf(os.Stderr, "assertion failed at index %d: expected Token.Data %q, got %q\n", i, exp.data, tok.Data)
			os.Exit(1)
		}
	}

	// Assertion 3: SelfClosingTagToken is returned when tokenizer encounters self-closing void elements
	zImg := html.NewTokenizer(strings.NewReader(`<img src="example.png"/>`))
	if tt := zImg.Next(); tt != html.SelfClosingTagToken {
		fmt.Fprintf(os.Stderr, "assertion failed: expected SelfClosingTagToken, got %s\n", tt.String())
		os.Exit(1)
	}

	// Assertion 4: CommentToken and DoctypeToken are correctly identified by tokenizer
	zDoc := html.NewTokenizer(strings.NewReader(`<!DOCTYPE html>`))
	if tt := zDoc.Next(); tt != html.DoctypeToken {
		fmt.Fprintf(os.Stderr, "assertion failed: expected DoctypeToken, got %s\n", tt.String())
		os.Exit(1)
	}
	zCom := html.NewTokenizer(strings.NewReader(`<!-- notice -->`))
	if tt := zCom.Next(); tt != html.CommentToken {
		fmt.Fprintf(os.Stderr, "assertion failed: expected CommentToken, got %s\n", tt.String())
		os.Exit(1)
	}

	// Assertion 5: ErrorToken is returned at end of input with io.EOF error
	ttEOF := z.Next()
	if ttEOF != html.ErrorToken {
		fmt.Fprintf(os.Stderr, "assertion failed: expected ErrorToken at end of input, got %s\n", ttEOF.String())
		os.Exit(1)
	}
	if z.Err() != io.EOF {
		fmt.Fprintf(os.Stderr, "assertion failed: expected io.EOF, got %v\n", z.Err())
		os.Exit(1)
	}

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