`, ``, …) which are not // escaped in any mode and would otherwise consume appended chrome. cases := []struct{ in, want string }{ {"hello world\n", "\n\nhello world\n\n"}, {"# heading\n", "\n\n\\# heading\n\n"}, {"> quote\n", "\n\n\\> quote\n\n"}, {"| a | b |\n", "\n\n\\| a | b |\n\n"}, // GFM table-row escaped in strict mode // CM §4.6 HTML block types 1-5 — escaped (blank-line-NON-terminating). {"\n", "\n\n\\\n\n"}, {"\n", "\n\n\\\n\n"}, {"\n", "\n\n\\\n\n"}, {"\n", "\n\n\\\n\n"}, {"```\ncode\n", "\n\n```\ncode\n```\n\n"}, // fence auto-close at EOF // Empty / strip-to-empty inputs short-circuit (no stray blank line). {"[x]: y\n", ""}, {"", ""}, } for _, c := range cases { got := Block(c.in) if got != c.want { t.Errorf("Block(%q) = %q, want %q", c.in, got, c.want) } // Idempotency: Block(Block(in)) must be byte-identical to // Block(in) for every input in the table. twice := Block(got) if twice != got { t.Errorf("Block not idempotent for %q: Block(once)=%q, Block(twice)=%q", c.in, got, twice) } } } func TestBlockRich(t *testing.T) { // BlockRich wraps every non-empty output with "\n\n" — CM §4.8 // blank lines — on BOTH sides, so user content is paragraph- // isolated from any realm chrome that precedes OR follows it. cases := []struct{ in, want string }{ // Block-level markdown that Block escapes — preserved by BlockRich. {"hello world\n", "\n\nhello world\n\n"}, {"# heading\n", "\n\n# heading\n\n"}, {"> quote\n", "\n\n> quote\n\n"}, {"- item\n", "\n\n- item\n\n"}, {"1. item\n", "\n\n1. item\n\n"}, {"---\n", "\n\n\\---\n\n"}, // first-line setext-h2 → escaped by qualifying-setext pre-pass {"***\n", "\n\n***\n\n"}, // thematic break NOT setext-h2 — preserved {"text\n===\n", "\n\ntext\n===\n\n"}, // deeper setext preserved (user-authored above) {"body\n===\nmore\n", "\n\nbody\n===\nmore\n\n"}, // cross-paragraph backward attack: realm `chrome\n\nbody\n===\nmore` keeps realm in its own paragraph // GFM tables PRESERVED in Rich mode. {"| a | b |\n", "\n\n| a | b |\n\n"}, {"| H |\n|---|\n| a |\n", "\n\n| H |\n|---|\n| a |\n\n"}, // full table renders as

// Realm-binding defenses STILL ON. {"\n", "\n\n\\\n\n"}, // CM §4.6 HTML block types 1-5 — escaped in Rich mode too // (defense is mode-independent). {"\n", "\n\n\\\n\n"}, {"\n", "\n\n\\\n\n"}, {"\n", "\n\n\\\n\n"}, {"\n", "\n\n\\\n\n"}, {"[t][l]\n", "\n\n\\[t\\]\\[l\\]\n\n"}, {"[^name]\n", "\n\n\\[^name\\]\n\n"}, // LRD-only input strips to nothing; empty-after-escape short- // circuits to "" so realm concatenation doesn't leak a stray // blank line. {"[x]: y\n", ""}, {"", ""}, // empty input → empty output, no stray blank line {"```\ncode\n", "\n\n```\ncode\n```\n\n"}, } for _, c := range cases { got := BlockRich(c.in) if got != c.want { t.Errorf("BlockRich(%q) = %q, want %q", c.in, got, c.want) } // Idempotency: BlockRich(BlockRich(in)) must be byte-identical // to BlockRich(in) for every input in the table. twice := BlockRich(got) if twice != got { t.Errorf("BlockRich not idempotent for %q: BlockRich(once)=%q, BlockRich(twice)=%q", c.in, got, twice) } } } func TestBlockRich_LeadingBlankLineGuaranteed(t *testing.T) { // Every non-empty result begins with "\n\n" so `chrome + // BlockRich(user)` cannot place the user's first line in the same // paragraph as the realm's last line (which would let a deeper // `===` or `|---|` in user content retroactively promote realm // chrome). for _, in := range []string{"x", "x\n", "# h", "- i\n- j", "| a |\n|---|\n| 1 |"} { got := BlockRich(in) if got == "" { continue } if !strings.HasPrefix(got, "\n\n") { t.Errorf("BlockRich(%q) = %q; expected leading '\\n\\n'", in, got) } } } func TestBlockRich_TrailingBlankLineGuaranteed(t *testing.T) { // Every non-empty result ends with "\n\n" so `BlockRich(user) + // chrome` cannot extend user's last paragraph into the realm's // next line (CM §5.2 lazy continuation, or a realm-supplied // `|---|` row retroactively promoting user's last line into a // `` header). for _, in := range []string{"x", "x\n", "# h", "- i\n- j", "| H |\n|---|\n| a |"} { got := BlockRich(in) if got == "" { continue } if !strings.HasSuffix(got, "\n\n") { t.Errorf("BlockRich(%q) = %q; expected trailing '\\n\\n'", in, got) } } } func TestBlockquoteRich(t *testing.T) { // BlockquoteRich strips BlockRich's leading "\n", line-prefixes // each remaining line with "> ", and emits "\n" on both ends: // leading "\n" prevents `chrome + BlockquoteRich(user)` from // landing the first `>` mid-line; trailing "\n\n" (blank line) // prevents `BlockquoteRich(user) + chrome` from pulling chrome // into the quote via CM §5.2 lazy continuation. cases := []struct{ name, in, want string }{ {"plain text", "hello world\n", "\n> hello world\n\n"}, {"atx heading preserved", "# heading\n", "\n> # heading\n\n"}, {"nested blockquote", "> nested\n", "\n> > nested\n\n"}, {"list item preserved", "- item\n", "\n> - item\n\n"}, {"ordered list preserved", "1. item\n", "\n> 1. item\n\n"}, {"first-line setext escaped", "---\n", "\n> \\---\n\n"}, {"deeper setext preserved", "text\n===\n", "\n> text\n> ===\n\n"}, {"thematic break asterisks preserved", "***\n", "\n> ***\n\n"}, // Realm-binding defenses still on. {"gno extension escaped", "\n", "\n> \\\n\n"}, {"ref-link use escaped", "[t][l]\n", "\n> \\[t\\]\\[l\\]\n\n"}, {"footnote escaped", "[^name]\n", "\n> \\[^name\\]\n\n"}, // LRDs are stripped by BlockRich entirely; trimming the // resulting bare "\n" leaves empty input and the helper // returns "" without emitting a blockquote. {"lrd alone strips to empty", "[x]: y\n", ""}, // Code fence autoclose at EOF lands inside the quote. {"unclosed fence autoclosed", "```\ncode\n", "\n> ```\n> code\n> ```\n\n"}, // Multi-paragraph preserves the inner blank line (rendered // as a quoted blank line `> \n`). {"multi-paragraph preserves blank", "a\n\nb\n", "\n> a\n> \n> b\n\n"}, // Empty / blank-only input collapses cleanly to "". {"empty input", "", ""}, // CRLF normalized through BlockRich. {"crlf normalized", "a\r\nb\n", "\n> a\n> b\n\n"}, // NUL replaced with U+FFFD by BlockRich. {"nul replaced", "x\x00y\n", "\n> x\uFFFDy\n\n"}, // Multiple trailing newlines collapse to the single trailing // blank line shape — output never ends with more than `\n\n`. {"multiple trailing newlines collapse", "foo\n\n\n", "\n> foo\n\n"}, // Internal tabs are preserved (BlockRich does not touch them). {"internal tab preserved", "a\tb\n", "\n> a\tb\n\n"}, // Whitespace-only input still yields a blockquote (the user // wrote literal spaces). The line-prefix loop emits `> ` plus // the original two spaces. {"whitespace-only input", " ", "\n> \n\n"}, } for _, c := range cases { got := BlockquoteRich(c.in) if got != c.want { t.Errorf("%s: BlockquoteRich(%q) = %q, want %q", c.name, c.in, got, c.want) } } } func TestBlockquoteRich_DoubleWrapNestsQuote(t *testing.T) { // Not idempotent: calling twice nests the quote one level // deeper. The aggressive TrimRight in BlockquoteRich also // collapses the inner trailing blank line, so the second pass // produces a clean `> > foo` nesting (no `> ` quoted blank in // the middle) plus the outer trailing blank line. once := BlockquoteRich("foo\n") twice := BlockquoteRich(once) if want := "\n> > foo\n\n"; twice != want { t.Errorf("BlockquoteRich(BlockquoteRich(%q)) = %q, want %q", "foo\n", twice, want) } } func TestBlockquoteRich_LeadingNewlineGuaranteed(t *testing.T) { // Every non-empty result starts with "\n" so realm concatenation // like `chrome + BlockquoteRich(user)` doesn't place `>` mid-line. for _, in := range []string{"x", "x\n", "# h", "- i\n- j"} { got := BlockquoteRich(in) if got == "" { continue } if got[0] != '\n' { t.Errorf("BlockquoteRich(%q) = %q; expected leading '\\n'", in, got) } } } func TestBlockquoteRich_TrailingBlankLineGuaranteed(t *testing.T) { // Every non-empty result ends with "\n\n" so realm concatenation // like `BlockquoteRich(user) + "more text"` doesn't pull "more // text" into the quote via CM §5.2 lazy continuation. for _, in := range []string{"x", "x\n", "# h", "- i\n- j", "para\n\nmore"} { got := BlockquoteRich(in) if got == "" { continue } if !strings.HasSuffix(got, "\n\n") { t.Errorf("BlockquoteRich(%q) = %q; expected trailing '\\n\\n'", in, got) } } } func TestBlockquoteRich_NoStrayEmptyQuotedLine(t *testing.T) { // BlockRich's own leading "\n" must be stripped before // line-prefixing — otherwise the output would start with a // useless `> \n` empty quoted line. got := BlockquoteRich("foo\n") if strings.HasPrefix(got, "\n> \n") { t.Errorf("BlockquoteRich leaked BlockRich's leading '\\n' as `> \\n`: %q", got) } } func TestNeuterLeadingSetextIfQualifying(t *testing.T) { cases := []struct{ name, in, want string }{ {"leading-setext-h1", "===\nbody\n", "\\===\nbody\n"}, {"leading-setext-h2", "---\nbody\n", "\\---\nbody\n"}, {"leading-setext-indented", " ===\nbody\n", " \\===\nbody\n"}, {"leading-setext-indented-4", " ===\nbody\n", " ===\nbody\n"}, // indented code {"leading-setext-trailing-ws", "=== \nbody\n", "\\=== \nbody\n"}, {"leading-setext-mixed-chars", "=-=-\nbody\n", "=-=-\nbody\n"}, // mixed; not setext {"leading-setext-has-content", "=== text\nbody\n", "=== text\nbody\n"}, // mixed content {"setext-deeper-untouched", "title\n===\nfoo\n", "title\n===\nfoo\n"}, {"leading-thematic-asterisk", "***\nbody\n", "***\nbody\n"}, // not setext, untouched {"leading-thematic-underscore", "___\nbody\n", "___\nbody\n"}, {"leading-blank-then-setext", "\n===\nbody\n", "\n\\===\nbody\n"}, {"leading-blank-ws-then-setext", " \n===\nbody\n", " \n\\===\nbody\n"}, {"text-first", "hello\n===\n", "hello\n===\n"}, // text before === — user-authored {"empty", "", ""}, {"all-blank", " \n\n", " \n\n"}, {"only-equals", "===", "\\==="}, } for _, c := range cases { if got := neuterLeadingSetextIfQualifying(c.in); got != c.want { t.Errorf("%s: neuterLeadingSetextIfQualifying(%q) = %q, want %q", c.name, c.in, got, c.want) } } } func TestLinkTitle(t *testing.T) { cases := []struct{ in, want string }{ {`he said "hi"`, `he said \"hi\"`}, {`it's nice`, `it\'s nice`}, {"line1\nline2", "line1 line2"}, } for _, c := range cases { if got := LinkTitle(c.in); got != c.want { t.Errorf("LinkTitle(%q) = %q, want %q", c.in, got, c.want) } } } func TestTableCell(t *testing.T) { cases := []struct{ in, want string }{ {"plain cell", "plain cell"}, {"a|b", `a\|b`}, {"a\tb", "a b"}, {"a*b|c", `a\*b\|c`}, } for _, c := range cases { if got := TableCell(c.in); got != c.want { t.Errorf("TableCell(%q) = %q, want %q", c.in, got, c.want) } } } func TestHTMLEscape(t *testing.T) { cases := []struct{ in, want string }{ {"plain", "plain"}, {"