github.com/russross/blackfriday/v2 v2.1.0: New

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 github.com/russross/blackfriday/v2.New in pkg:golang/github.com/russross/blackfriday/v2@v2.1.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/russross/blackfriday/v2@v2.1.0
Demonstrate these symbols/APIs:
  - github.com/russross/blackfriday/v2.New

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 sample

import (
	"strings"
	"testing"

	"github.com/russross/blackfriday/v2"
)

func TestContractBlackfridayNew(t *testing.T) {
	// 1. Verify blackfriday.New returns a valid Markdown processor
	mdDefault := NewParser()
	if mdDefault == nil {
		t.Fatal("expected non-nil Markdown parser from NewParser()")
	}

	// 2. Verify basic parsing creates an AST with Document and Paragraph nodes
	input := []byte("# Main Title\n\nThis is a paragraph with **bold** text.")
	doc := Parse(mdDefault, input)
	if doc == nil {
		t.Fatal("expected non-nil AST root node from Parse()")
	}
	if doc.Type != blackfriday.Document {
		t.Fatalf("expected root node type Document, got %v", doc.Type)
	}

	headings := ExtractHeadings(doc)
	if len(headings) != 1 || headings[0] != "Main Title" {
		t.Fatalf("expected headings [\"Main Title\"], got %v", headings)
	}

	// 3. Verify blackfriday.New with Extensions parses extended features (tables, fenced code)
	mdExtended := NewParser(blackfriday.WithExtensions(blackfriday.CommonExtensions))
	extendedInput := []byte("## Section 2\n\n```go\nfunc main() {}\n```\n\n| Name | Value |\n| --- | --- |\n| Test | 123 |\n")
	docExtended := Parse(mdExtended, extendedInput)
	if docExtended == nil {
		t.Fatal("expected non-nil AST for extended markdown")
	}

	var hasCodeBlock, hasTable bool
	docExtended.Walk(func(node *blackfriday.Node, entering bool) blackfriday.WalkStatus {
		if entering {
			if node.Type == blackfriday.CodeBlock {
				hasCodeBlock = true
			}
			if node.Type == blackfriday.Table {
				hasTable = true
			}
		}
		return blackfriday.GoToNext
	})

	if !hasCodeBlock {
		t.Fatal("expected AST to contain CodeBlock node")
	}
	if !hasTable {
		t.Fatal("expected AST to contain Table node")
	}

	// 4. Verify rendering AST to HTML output
	renderer := blackfriday.NewHTMLRenderer(blackfriday.HTMLRendererParameters{
		Flags: blackfriday.CommonHTMLFlags,
	})
	htmlOutput := RenderHTML(docExtended, renderer)
	if !strings.Contains(htmlOutput, "<h2>Section 2</h2>") {
		t.Fatalf("expected rendered HTML to contain '<h2>Section 2</h2>', got:\n%s", htmlOutput)
	}
	if !strings.Contains(htmlOutput, "<pre><code class=\"language-go\">func main() {}") {
		t.Fatalf("expected rendered HTML to contain go code block, got:\n%s", htmlOutput)
	}
	if !strings.Contains(htmlOutput, "<table>") {
		t.Fatalf("expected rendered HTML to contain '<table>', got:\n%s", htmlOutput)
	}
}

{"case":{"caseId":"case:sha256:520c2b8677a58c3aae9d7df628e481ab8e21c93389b6dafc0948910b761b4fe1","contract":["blackfriday.New constructs a Markdown processor with default or custom options","Markdown.Parse parses Markdown source bytes into an AST Node tree","blackfriday.WithExtensions enables parsing of extended syntax like tables and code blocks","AST nodes can be traversed and rendered to HTML using HTMLRenderer"],"goal":"verify github.com/russross/blackfriday/v2.New in pkg:golang/github.com/russross/blackfriday/v2@v2.1.0","kind":"HOW","packages":["pkg:golang/github.com/russross/blackfriday/v2@v2.1.0"],"schemaVersion":1,"symbols":["github.com/russross/blackfriday/v2.New"]},"contractCommand":["go","test","./..."],"environment":{"arch":"amd64","compiler":"go","compilerVersion":"1.26.6","distro":"ubuntu","ecosystem":"golang","language":"go","languageVersion":"1.26.6","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","runtime":"go","runtimeVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/russross/blackfriday/v2@v2.1.0"],"schemaVersion":1,"subject":"pkg:golang/github.com/russross/blackfriday/v2@v2.1.0","symbols":["github.com/russross/blackfriday/v2.New"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require github.com/russross/blackfriday/v2 v2.1.0

github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf35Ld67mk=
github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=

package sample

import (
	"bytes"

	"github.com/russross/blackfriday/v2"
)

// NewParser creates a Markdown processor configured with the given options.
func NewParser(opts ...blackfriday.Option) *blackfriday.Markdown {
	return blackfriday.New(opts...)
}

// Parse converts markdown bytes into an AST root node using the processor.
func Parse(m *blackfriday.Markdown, input []byte) *blackfriday.Node {
	return m.Parse(input)
}

// ExtractHeadings traverses the AST and collects text from all heading nodes.
func ExtractHeadings(node *blackfriday.Node) []string {
	var headings []string
	node.Walk(func(n *blackfriday.Node, entering bool) blackfriday.WalkStatus {
		if entering && n.Type == blackfriday.Heading {
			var headingText string
			for child := n.FirstChild; child != nil; child = child.Next {
				if child.Type == blackfriday.Text || child.Type == blackfriday.Code {
					headingText += string(child.Literal)
				}
			}
			headings = append(headings, headingText)
		}
		return blackfriday.GoToNext
	})
	return headings
}

// RenderHTML renders the AST to an HTML string using an HTMLRenderer.
func RenderHTML(ast *blackfriday.Node, renderer *blackfriday.HTMLRenderer) string {
	var buf bytes.Buffer
	renderer.RenderHeader(&buf, ast)
	ast.Walk(func(node *blackfriday.Node, entering bool) blackfriday.WalkStatus {
		return renderer.RenderNode(&buf, node, entering)
	})
	renderer.RenderFooter(&buf, ast)
	return buf.String()
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/russross/blackfriday/v2.New in pkg:golang/github.com/russross/blackfriday/v2@v2.1.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/russross/blackfriday/v2@v2.1.0"
  ],
  "symbols": [
    "github.com/russross/blackfriday/v2.New"
  ]
}