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

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.CommonHTMLFlags 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.CommonHTMLFlags
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

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:sha256:1fa13072b62176f779ec3e369c98873de290d7d3fad558ee4919deafeac345d2","constraints":{"executionContext":"go"},"contract":["blackfriday.CommonHTMLFlags combines UseXHTML, Smartypants, SmartypantsFractions, SmartypantsDashes, and SmartypantsLatexDashes bit flags.","Configuring an HTMLRenderer with CommonHTMLFlags renders XHTML self-closing tags and performs Smartypants typographic conversions for quotes, dashes, and fractions."],"goal":"verify github.com/russross/blackfriday/v2.CommonHTMLFlags 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.CommonHTMLFlags"]},"contractCommand":["go","test","./..."],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","executionContext":"go","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","runtime":"go","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.CommonHTMLFlags"],"verifierAdapter":"golang@1"}

package blackfridayflags_test

import (
	"strings"
	"testing"

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

func TestCommonHTMLFlagsComposition(t *testing.T) {
	expectedFlags := blackfriday.UseXHTML |
		blackfriday.Smartypants |
		blackfriday.SmartypantsFractions |
		blackfriday.SmartypantsDashes |
		blackfriday.SmartypantsLatexDashes

	if blackfriday.CommonHTMLFlags != expectedFlags {
		t.Fatalf("expected CommonHTMLFlags to match composition, got %v, want %v",
			blackfriday.CommonHTMLFlags, expectedFlags)
	}

	// Verify individual bit flags are active within CommonHTMLFlags
	if blackfriday.CommonHTMLFlags&blackfriday.UseXHTML == 0 {
		t.Errorf("expected UseXHTML flag to be set in CommonHTMLFlags")
	}
	if blackfriday.CommonHTMLFlags&blackfriday.Smartypants == 0 {
		t.Errorf("expected Smartypants flag to be set in CommonHTMLFlags")
	}
	if blackfriday.CommonHTMLFlags&blackfriday.SmartypantsFractions == 0 {
		t.Errorf("expected SmartypantsFractions flag to be set in CommonHTMLFlags")
	}
	if blackfriday.CommonHTMLFlags&blackfriday.SmartypantsDashes == 0 {
		t.Errorf("expected SmartypantsDashes flag to be set in CommonHTMLFlags")
	}
	if blackfriday.CommonHTMLFlags&blackfriday.SmartypantsLatexDashes == 0 {
		t.Errorf("expected SmartypantsLatexDashes flag to be set in CommonHTMLFlags")
	}
}

func TestCommonHTMLFlagsRenderingBehavior(t *testing.T) {
	input := []byte("\"Smart quotes\" -- en-dash --- em-dash 1/2\n\n---")

	// 1. Render with CommonHTMLFlags explicitly configured in HTMLRendererParameters
	renderer := blackfriday.NewHTMLRenderer(blackfriday.HTMLRendererParameters{
		Flags: blackfriday.CommonHTMLFlags,
	})
	output := string(blackfriday.Run(input, blackfriday.WithRenderer(renderer)))

	// Check XHTML self-closing tag for horizontal rule
	if !strings.Contains(output, "<hr />") {
		t.Errorf("expected XHTML horizontal rule <hr />, got: %s", output)
	}

	// Check Smartypants curly quotes
	if !strings.Contains(output, "&ldquo;Smart quotes&rdquo;") {
		t.Errorf("expected smart quotes &ldquo;Smart quotes&rdquo;, got: %s", output)
	}

	// Check Smartypants dashes
	if !strings.Contains(output, "&ndash;") || !strings.Contains(output, "&mdash;") {
		t.Errorf("expected &ndash; and &mdash;, got: %s", output)
	}

	// Check Smartypants fractions (rendered as superscript/frasl/subscript)
	if !strings.Contains(output, "<sup>1</sup>&frasl;<sub>2</sub>") {
		t.Errorf("expected <sup>1</sup>&frasl;<sub>2</sub>, got: %s", output)
	}

	// 2. Render with HTMLFlagsNone to verify that CommonHTMLFlags transformations are disabled
	plainRenderer := blackfriday.NewHTMLRenderer(blackfriday.HTMLRendererParameters{
		Flags: blackfriday.HTMLFlagsNone,
	})
	plainOutput := string(blackfriday.Run(input, blackfriday.WithRenderer(plainRenderer)))

	if strings.Contains(plainOutput, "&ldquo;") || strings.Contains(plainOutput, "&rdquo;") {
		t.Errorf("HTMLFlagsNone should not contain smart quotes, got: %s", plainOutput)
	}
	if strings.Contains(plainOutput, "&frasl;") {
		t.Errorf("HTMLFlagsNone should not contain fraction slash entities, got: %s", plainOutput)
	}
	if strings.Contains(plainOutput, "<hr />") {
		t.Errorf("HTMLFlagsNone (without UseXHTML) should use <hr>, got: %s", plainOutput)
	}
}

module example.com/blackfridayflags

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=

{
  "schemaVersion": 1,
  "goal": "verify github.com/russross/blackfriday/v2.CommonHTMLFlags 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.CommonHTMLFlags"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}