/** * Regression tests for Telegram UI/compat rendering helpers * Covers nested lists, code blocks, tables, links, quotes, chunking, and other Telegram-specific render edge cases */ import assert from "node:assert/strict"; import test from "node:test"; import { chunkHtmlPreservingTags, escapeHtml, escapeHtmlAttribute, MAX_MESSAGE_LENGTH, renderTelegramMessage, } from "../lib/rendering.ts"; function countMatches(text: string, pattern: RegExp): number { return text.match(pattern)?.length ?? 0; } test("HTML helpers escape text and attribute contexts", () => { assert.equal(escapeHtml("&value"), "<tag>&value"); assert.equal( escapeHtmlAttribute(`"quoted" 'value' & `), ""quoted" 'value' & <tag>", ); }); test("HTML helpers chunk long text while preserving open tags", () => { const chunks = chunkHtmlPreservingTags(`${"x".repeat(10)}`, 12); assert.deepEqual(chunks, ["xxxxx", "xxxxx"]); }); test("HTML helpers do not reopen void tags across chunks", () => { const chunks = chunkHtmlPreservingTags(`a
${"b".repeat(10)}`, 8); assert.deepEqual(chunks, ["a
bbb", "bbbbbbbb".slice(0, 7)]); }); test("Malformed and boundary markdown renders safely", () => { const cases = [ "", "```ts\nconst raw = '**not bold**'", `${"x".repeat(MAX_MESSAGE_LENGTH + 250)} end`, `surrogate-boundary: ${"🙂".repeat(120)}\uD83D`, [ "> level 1", "> > level 2", "> > > level 3", "> > > > level 4", "> **bold quote", ].join("\n"), ]; for (const markdown of cases) { let chunks: ReturnType = []; assert.doesNotThrow(() => { chunks = renderTelegramMessage(markdown, { mode: "markdown" }); }); for (const chunk of chunks) { assert.ok(chunk.text.length <= MAX_MESSAGE_LENGTH); assert.equal( countMatches(chunk.text, /

/g), countMatches(chunk.text, /<\/blockquote>/g), ); assert.equal( countMatches(chunk.text, //g), countMatches(chunk.text, /<\/b>/g), ); assert.equal( countMatches(chunk.text, //g), countMatches(chunk.text, /<\/i>/g), ); assert.equal( countMatches(chunk.text, /
/g), countMatches(chunk.text, /<\/pre>/g), ); } } }); test("Nested lists stay out of code blocks", () => { const chunks = renderTelegramMessage( "- Level 1\n - Level 2\n - Level 3 with **bold** text", { mode: "markdown" }, ); assert.ok(chunks.length > 0); assert.equal( chunks.some((chunk) => chunk.text.includes("
")), false, ); assert.equal( chunks.some((chunk) => chunk.text.includes("- Level 3 with bold text"), ), true, ); }); test("Fenced code blocks preserve literal markdown", () => { const chunks = renderTelegramMessage('~~~ts\nconst value = "**raw**";\n~~~', { mode: "markdown", }); assert.equal(chunks.length, 1); assert.match(chunks[0]?.text ?? "", //); assert.match(chunks[0]?.text ?? "", /\*\*raw\*\*/); }); test("Underscores inside words do not become italic", () => { const chunks = renderTelegramMessage("Path: foo_bar_baz.txt and **bold**", { mode: "markdown", }); assert.equal(chunks.length, 1); assert.equal((chunks[0]?.text ?? "").includes("bar"), false); assert.match(chunks[0]?.text ?? "", /bold<\/b>/); }); test("Bold markdown can span soft line breaks", () => { const chunks = renderTelegramMessage( "Скорее: **архитектурно — да,\nпрактически — почти**.", { mode: "markdown" }, ); assert.equal(chunks.length, 1); assert.match( chunks[0]?.text ?? "", /Скорее: архитектурно — да,\nпрактически — почти<\/b>\./, ); }); test("Quoted nested lists stay in blockquote rendering", () => { const chunks = renderTelegramMessage( "> Quoted intro\n> - nested item\n> - deeper item", { mode: "markdown" }, ); assert.equal(chunks.length, 1); assert.match(chunks[0]?.text ?? "", //); assert.match(chunks[0]?.text ?? "", /nested item/); assert.match(chunks[0]?.text ?? "", /-<\/code> nested item/); assert.equal((chunks[0]?.text ?? "").includes(""), false); }); test("Numbered lists use monospace numeric markers", () => { const chunks = renderTelegramMessage("1. first\n 2. second", { mode: "markdown", }); assert.equal(chunks.length, 1); assert.match(chunks[0]?.text ?? "", /1\.<\/code> first/); assert.match(chunks[0]?.text ?? "", /2\.<\/code> second/); }); test("Ordered task lists preserve numeric markers in rendering", () => { const markdown = "1. [x] first\n2. [ ] second"; const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.equal(chunks.length, 1); assert.match( chunks[0]?.text ?? "", /1\.<\/code> \[x\]<\/code> first/, ); assert.match( chunks[0]?.text ?? "", /2\.<\/code> \[ \]<\/code> second/, ); }); test("Leading indentation on the first markdown line stays intact", () => { const markdown = " - nested bullet\n - nested child"; const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.equal(chunks.length, 1); assert.match( chunks[0]?.text ?? "", /^\u00A0\u00A0-<\/code> nested bullet/m, ); assert.match( chunks[0]?.text ?? "", /^\u00A0\u00A0\u00A0\u00A0-<\/code> nested child/m, ); }); test("UI/compat rendering preserves multiple blank lines between blocks", () => { const markdown = "# Title\n\n\nParagraph\n\n\n> Quote"; const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.equal(chunks.length, 1); assert.match( chunks[0]?.text ?? "", /Title<\/b>\n\n\nParagraph\n\n\nQuote<\/blockquote>/, ); }); test("UI/compat rendering preserves original blank-line spacing across block transitions", () => { const cases = [ { markdown: "Para\n\n\n```ts\nconst x = 1\n```", finalText: 'Para\n\n\nconst x = 1', }, { markdown: "```ts\nconst x = 1\n```\n\n\nPara", finalText: 'const x = 1\n\n\nPara', }, { markdown: "Para\n\n\n- item", finalText: "Para\n\n\n- item", }, { markdown: "Para\n\n\n> Quote", finalText: "Para\n\n\nQuote", }, ]; for (const testCase of cases) { const finalChunks = renderTelegramMessage(testCase.markdown, { mode: "markdown", }); assert.equal(finalChunks.length, 1); assert.equal(finalChunks[0]?.text ?? "", testCase.finalText); } }); test("Headings keep visible spacing before following code blocks even without source blank lines", () => { const markdown = "### Title\n```ts\nconst x = 1\n```"; const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.equal(chunks.length, 1); assert.match( chunks[0]?.text ?? "", /Title<\/b>\n\nconst x = 1<\/code><\/pre>/, ); }); test("Standalone checkbox-looking prose stays literal outside task lists", () => { const markdown = "Use [ ] as a placeholder and keep [x] literal"; const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.equal(chunks.length, 1); assert.equal((chunks[0]?.text ?? "").includes("[ ]"), false); assert.equal((chunks[0]?.text ?? "").includes("[x]"), false); assert.match(chunks[0]?.text ?? "", /Use \[ \] as a placeholder/); assert.match(chunks[0]?.text ?? "", /keep \[x\] literal/); }); test("Nested blockquotes flatten into one Telegram blockquote with indentation", () => { const chunks = renderTelegramMessage("> outer\n>> inner\n>>> deepest", { mode: "markdown", }); assert.equal(chunks.length, 1); assert.equal((chunks[0]?.text.match(//g) ?? []).length, 1); assert.equal((chunks[0]?.text.match(/<\/blockquote>/g) ?? []).length, 1); assert.match(chunks[0]?.text ?? "", /outer/); assert.match(chunks[0]?.text ?? "", /\u00A0\u00A0inner/); assert.match(chunks[0]?.text ?? "", /\u00A0\u00A0\u00A0\u00A0deepest/); }); test("UI/compat Markdown tables render as literal monospace blocks without outer side borders", () => { const chunks = renderTelegramMessage( "| Name | Value |\n| --- | --- |\n| **x** | `y` |", { mode: "markdown" }, ); assert.equal(chunks.length, 1); assert.match(chunks[0]?.text ?? "", //); assert.equal((chunks[0]?.text ?? "").includes("x"), false); assert.match(chunks[0]?.text ?? "", /Name\s+\|\s+Value/); assert.match(chunks[0]?.text ?? "", /x\s+\|\s+y/); assert.equal((chunks[0]?.text ?? "").includes("| Name |"), false); assert.equal((chunks[0]?.text ?? "").includes("| x |"), false); }); test("Markdown table padding uses emoji grapheme display width", () => { const chunks = renderTelegramMessage( "| Icon | Name |\n| --- | --- |\n| 👩‍💻 | dev |\n| ✅ | done |\n| 1️⃣ | key |", { mode: "markdown" }, ); assert.equal(chunks.length, 1); assert.match(chunks[0]?.text ?? "", /Icon \| Name/); assert.match(chunks[0]?.text ?? "", /👩‍💻 {3}\| dev /u); assert.match(chunks[0]?.text ?? "", /✅ {3}\| done/u); assert.match(chunks[0]?.text ?? "", /1️⃣ {3}\| key /u); }); test("Markdown table padding handles CJK and combining marks", () => { const chunks = renderTelegramMessage( "| Word | Note |\n| --- | --- |\n| é | acute |\n| 東京 | city |", { mode: "markdown" }, ); assert.equal(chunks.length, 1); assert.match(chunks[0]?.text ?? "", /Word \| Note /); assert.match(chunks[0]?.text ?? "", /é {4}\| acute/u); assert.match(chunks[0]?.text ?? "", /東京 \| city /u); }); test("Links, code spans, and underscore-heavy text coexist safely", () => { const chunks = renderTelegramMessage( "See [docs](https://example.com), run `foo_bar()` and keep foo_bar.txt literal", { mode: "markdown" }, ); assert.equal(chunks.length, 1); assert.match( chunks[0]?.text ?? "", /docs<\/a>/, ); assert.match(chunks[0]?.text ?? "", /foo_bar<\/code>/); assert.equal((chunks[0]?.text ?? "").includes("bar"), false); }); test("HTML attributes are escaped or sanitized in generated Telegram markup", () => { const linkChunks = renderTelegramMessage( '[quoted]()', { mode: "markdown" }, ); assert.match( linkChunks[0]?.text ?? "", /quoted<\/a>/, ); const codeChunks = renderTelegramMessage( '```ts"onclick=bad\nconst value = 1;\n```', { mode: "markdown" }, ); assert.match( codeChunks[0]?.text ?? "", //, ); assert.equal((codeChunks[0]?.text ?? "").includes('"onclick'), false); }); test("HTML mode chunks long messages below Telegram limits", () => { const chunks = renderTelegramMessage("x".repeat(5000), { mode: "html", }); assert.ok(chunks.length > 1); for (const chunk of chunks) { assert.equal(chunk.parseMode, "HTML"); assert.ok(chunk.text.length <= MAX_MESSAGE_LENGTH); } }); test("HTML mode keeps tags balanced across long chunk boundaries", () => { const chunks = renderTelegramMessage( `${"x".repeat(5000)}`, { mode: "html" }, ); assert.ok(chunks.length > 1); for (const chunk of chunks) { assert.equal(chunk.parseMode, "HTML"); assert.ok(chunk.text.length <= MAX_MESSAGE_LENGTH); assert.equal( (chunk.text.match(//g) ?? []).length, (chunk.text.match(/<\/blockquote>/g) ?? []).length, ); assert.equal( (chunk.text.match(//g) ?? []).length, (chunk.text.match(/<\/b>/g) ?? []).length, ); } }); test("Links degrade or normalize safely across supported and unsupported markdown forms", () => { const markdown = [ "[**Bold** label](https://example.com/path)", "[Docs](https://example.com/a_(b))", '[Title](https://example.com/path "Tooltip")', "[Relative](./docs/README.md)", "[Ref][docs]", "", "[docs]: https://example.com/ref", "", "Footnote[^1]", "", "[^1]: Footnote body", ].join("\n"); const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.equal(chunks.length, 1); assert.match( chunks[0]?.text ?? "", /Bold label<\/a>/, ); assert.match( chunks[0]?.text ?? "", /Docs<\/a>/, ); assert.match( chunks[0]?.text ?? "", /Title<\/a>/, ); assert.equal( (chunks[0]?.text ?? "").includes(''), false, ); assert.match(chunks[0]?.text ?? "", /Relative/); assert.equal( (chunks[0]?.text ?? "").includes(''), false, ); assert.match(chunks[0]?.text ?? "", /\[Ref\]\[docs\]/); assert.match(chunks[0]?.text ?? "", /Footnote\[\^1\]/); assert.match(chunks[0]?.text ?? "", /\[\^1\]: Footnote body/); }); test("Long quoted blocks stay chunked with balanced blockquote tags", () => { const markdown = Array.from( { length: 500 }, (_, index) => `> quoted **${index}** line`, ).join("\n"); const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.ok(chunks.length > 1); for (const chunk of chunks) { assert.ok(chunk.text.length <= MAX_MESSAGE_LENGTH); assert.equal( (chunk.text.match(//g) ?? []).length, (chunk.text.match(/<\/blockquote>/g) ?? []).length, ); } }); test("Long UI/compat Markdown messages stay chunked below Telegram limits", () => { const markdown = Array.from( { length: 600 }, (_, index) => `- item **${index}**`, ).join("\n"); const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.ok(chunks.length > 1); for (const chunk of chunks) { assert.ok(chunk.text.length <= MAX_MESSAGE_LENGTH); assert.equal( (chunk.text.match(//g) ?? []).length, (chunk.text.match(/<\/b>/g) ?? []).length, ); } }); test("Long mixed links and code spans stay chunked with balanced inline tags", () => { const markdown = Array.from( { length: 450 }, (_, index) => `Paragraph ${index}: see [docs ${index}](https://example.com/${index}), run \`code_${index}()\`, and keep foo_bar_${index}.txt literal`, ).join("\n\n"); const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.ok(chunks.length > 1); for (const chunk of chunks) { assert.ok(chunk.text.length <= MAX_MESSAGE_LENGTH); assert.equal( (chunk.text.match(//g) ?? []).length, ); assert.equal( (chunk.text.match(//g) ?? []).length, (chunk.text.match(/<\/code>/g) ?? []).length, ); assert.equal((chunk.text ?? "").includes("bar"), false); } }); test("Long multi-block markdown keeps quotes and code fences structurally balanced", () => { const markdown = Array.from({ length: 120 }, (_, index) => { return [ `## Section ${index}`, `> quoted **${index}** line`, `- item ${index}`, "```ts", `const value_${index} = "**raw**";`, "```", ].join("\n"); }).join("\n\n"); const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.ok(chunks.length > 1); for (const chunk of chunks) { assert.ok(chunk.text.length <= MAX_MESSAGE_LENGTH); assert.equal( (chunk.text.match(//g) ?? []).length, (chunk.text.match(/<\/blockquote>/g) ?? []).length, ); assert.equal( (chunk.text.match(/<\/pre>/g) ?? []).length, ); } }); test("Chunked mixed block transitions keep quote and list structure balanced", () => { const markdown = Array.from({ length: 260 }, (_, index) => { return [ `> quoted **${index}** intro`, `> continuation ${index}`, `- item ${index}`, `plain paragraph ${index} with [link](https://example.com/${index})`, ].join("\n"); }).join("\n\n"); const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.ok(chunks.length > 1); for (const chunk of chunks) { assert.ok(chunk.text.length <= MAX_MESSAGE_LENGTH); assert.equal( (chunk.text.match(//g) ?? []).length, (chunk.text.match(/<\/blockquote>/g) ?? []).length, ); assert.equal( (chunk.text.match(//g) ?? []).length, ); } }); test("Chunked code fence transitions keep code blocks closed before following prose", () => { const markdown = Array.from({ length: 220 }, (_, index) => { return [ "```ts", `const block_${index} = "value_${index}";`, "```", `After code **${index}** and \`inline_${index}()\``, ].join("\n"); }).join("\n\n"); const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.ok(chunks.length > 1); for (const chunk of chunks) { assert.ok(chunk.text.length <= MAX_MESSAGE_LENGTH); assert.equal( (chunk.text.match(/<\/pre>/g) ?? []).length, ); assert.equal( (chunk.text.match(//g) ?? []).length, (chunk.text.match(/<\/code>/g) ?? []).length, ); } }); test("Long inline formatting paragraphs stay balanced across chunk boundaries", () => { const markdown = Array.from({ length: 500 }, (_, index) => { return `Segment ${index} keeps **bold_${index}** with \`code_${index}()\`, [link_${index}](https://example.com/${index}), and foo_bar_${index}.txt literal.`; }).join(" "); const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.ok(chunks.length > 1); for (const chunk of chunks) { assert.ok(chunk.text.length <= MAX_MESSAGE_LENGTH); assert.equal( (chunk.text.match(//g) ?? []).length, (chunk.text.match(/<\/b>/g) ?? []).length, ); assert.equal( (chunk.text.match(//g) ?? []).length, ); assert.equal( (chunk.text.match(//g) ?? []).length, (chunk.text.match(/<\/code>/g) ?? []).length, ); assert.equal(chunk.text.includes("bar"), false); } }); test("Realistic Markdown fixtures render safely for UI/compat surfaces", () => { const fixtures = [ [ "Here is the UI action plan:", "", "1. [x] Snapshot the database", "2. [ ] Apply the patch with `pnpm db:migrate`", "3. [ ] Verify [Grafana](https://example.com/dashboards/db)", "", "> Note: keep `user_id` and `team_id` untouched.", "", "```sql", "ALTER TABLE users ADD COLUMN team_id uuid; -- **literal**", "```", ].join("\n"), [ "### Comparison", "| Option | Pros | Cons |", "| --- | --- | --- |", "| A | Fast | More foo_bar flags |", "| B | Safer | Requires rollback notes |", "", "Unsupported relative link: [local](./notes.md)", "Supported link: [docs](https://example.com/path?q=a_b)", ].join("\n"), [ "The JSON payload should stay literal:", "", "```json", '{ "markdown": "**not bold**", "path": "foo_bar/baz" }', "```", "", "Nested quote from interactive compatibility message:", "> outer", ">> inner with **bold**", ].join("\n"), ]; for (const markdown of fixtures) { const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.ok(chunks.length > 0); for (const chunk of chunks) { assert.equal(chunk.parseMode, "HTML"); assert.ok(chunk.text.length <= MAX_MESSAGE_LENGTH); assert.equal( countMatches(chunk.text, //g), ); assert.equal( countMatches(chunk.text, //g), countMatches(chunk.text, /<\/blockquote>/g), ); assert.equal( countMatches(chunk.text, /<\/pre>/g), ); assert.equal(chunk.text.includes("bar"), false); } } }); test("Chunked list, code, quote, and prose cycles stay balanced across transitions", () => { const markdown = Array.from({ length: 180 }, (_, index) => { return [ `- list item **${index}**`, "```ts", `const cycle_${index} = "value_${index}";`, "```", `> quoted ${index} with [link](https://example.com/${index})`, `Plain paragraph ${index} with \`inline_${index}()\``, ].join("\n"); }).join("\n\n"); const chunks = renderTelegramMessage(markdown, { mode: "markdown", }); assert.ok(chunks.length > 1); for (const chunk of chunks) { assert.ok(chunk.text.length <= MAX_MESSAGE_LENGTH); assert.equal( (chunk.text.match(/<\/pre>/g) ?? []).length, ); assert.equal( (chunk.text.match(//g) ?? []).length, (chunk.text.match(/<\/blockquote>/g) ?? []).length, ); assert.equal( (chunk.text.match(//g) ?? []).length, ); } });