Text encoding test files

UTF-8 Text (LF)

A UTF-8 text file with Unix (LF) line endings and no byte-order mark, containing accented and symbol characters — for testing charset detection.

File: TXT · Text Encodings · UTF-8 (no BOM)
Use case: Encoding detection

UTF-8 Text with BOM (CRLF)

A UTF-8 text file that starts with a byte-order mark (EF BB BF) and uses Windows (CRLF) line endings — for testing BOM handling and line-ending detection.

File: TXT · Text Encodings · UTF-8 with BOM
Use case: Encoding detection

UTF-16 LE Text (CRLF)

A UTF-16 little-endian text file with a BOM (FF FE) and CRLF line endings — for testing wide-character decoding and encoding detection.

File: TXT · Text Encodings · UTF-16 LE with BOM
Use case: Encoding detection

UTF-16 BE Text (BOM)

A UTF-16 big-endian text file with a BOM (FE FF) and CRLF line endings — for testing wide-character decoding and byte-order detection.

File: TXT · Text Encodings · UTF-16 BE with BOM
Use case: Encoding detection

UTF-32 LE Text (BOM)

A UTF-32 little-endian text file with a BOM (FF FE 00 00) — four bytes per code point, for testing full-width Unicode decoders and byte-order handling.

File: TXT · Text Encodings · UTF-32 LE with BOM
Use case: Encoding detection

Latin-1 (ISO-8859-1) Text

A single-byte Latin-1 (ISO-8859-1) text file using high-range accented characters — for testing legacy 8-bit charset detection and transcoding to UTF-8.

File: TXT · Text Encodings · ISO-8859-1 (Latin-1)
Use case: Encoding detection

Windows-1252 Text

A Windows-1252 text file using the 0x80–0x9F range (smart quotes, em dash, euro, bullet) that naive Latin-1 decoders get wrong — for testing codepage detection and transcoding.

File: TXT · Text Encodings · Windows-1252 (CP1252)
Use case: Encoding detection

Shift-JIS Japanese Text

A Shift-JIS encoded Japanese text file — a multi-byte East-Asian encoding, for testing CJK charset detection and Shift-JIS→UTF-8 conversion.

File: TXT · Text Encodings · Japanese
Use case: Encoding detection

Mixed Line Endings Text

A UTF-8 text file that deliberately mixes LF, CRLF, and lone-CR line endings within one file — for testing newline normalisation and line-counting logic.

File: TXT · Text Encodings · UTF-8
Use case: Encoding detection

Right-to-Left / Bidi Text

A UTF-8 file mixing left-to-right and right-to-left scripts (Arabic and Hebrew alongside English) — for testing bidirectional text handling, reordering, and rendering.

File: TXT · Text Encodings · UTF-8
Use case: Encoding detection

Preview of Emoji & ZWJ Sequences Text — Actual file preview for Emoji & ZWJ Sequences Text

A UTF-8 file of emoji including zero-width-joiner sequences, regional-indicator flag pairs, and skin-tone modifiers — multi-code-point grapheme clusters for testing grapheme segmentation and display-width calculation.

File: TXT · Text Encodings · UTF-8
Use case: Encoding detection

Combining Marks (NFC vs NFD) Text

A UTF-8 file with the same words in both NFC (precomposed) and NFD (decomposed combining marks) normalisation forms — for testing normalisation-aware comparison, search, and dedup.

File: TXT · Text Encodings · UTF-8
Use case: Encoding detection

Very Long Single Line Text

A UTF-8 file consisting of a single very long line (~18,000 characters with no interior newline) — for testing editors, buffers, and line-oriented parsers against long-line handling.

File: TXT · Text Encodings · UTF-8
Use case: Encoding detection

Markdown Twin — Tasklist (CommonMark)

CommonMark-leaning Markdown twin for “tasklist” — compare against the GFM variant.

File: MD · Markdown Twins
Use case: Editor testingEncoding detection· Paired fixture

Markdown Twin — Table (CommonMark)

CommonMark-leaning Markdown twin for “table” — compare against the GFM variant.

File: MD · Markdown Twins
Use case: Editor testingEncoding detection· Paired fixture

Markdown Twin — Strikethrough (CommonMark)

CommonMark-leaning Markdown twin for “strikethrough” — compare against the GFM variant.

File: MD · Markdown Twins
Use case: Editor testingEncoding detection· Paired fixture

Markdown Twin — Autolink (CommonMark)

CommonMark-leaning Markdown twin for “autolink” — compare against the GFM variant.

File: MD · Markdown Twins
Use case: Editor testingEncoding detection· Paired fixture

Markdown Twin — Fenced-Lang (CommonMark)

CommonMark-leaning Markdown twin for “fenced-lang” — compare against the GFM variant.

File: MD · Markdown Twins
Use case: Editor testingEncoding detection· Paired fixture

Markdown Twin — Emoji-Ish (CommonMark)

CommonMark-leaning Markdown twin for “emoji-ish” — compare against the GFM variant.

File: MD · Markdown Twins
Use case: Editor testingEncoding detection· Paired fixture

LaTeX Article — On Sampling Rates (.tex)

SAMPLE LaTeX article “On Sampling Rates” with abstract, equation, and \cite to a twin .bib.

File: TEX · Latex Bib
Use case: Editor testingEncoding detection· Paired fixture

LaTeX Article — Notes on Information Entropy (.tex)

SAMPLE LaTeX article “Notes on Information Entropy” with abstract, equation, and \cite to a twin .bib.

File: TEX · Latex Bib
Use case: Editor testingEncoding detection· Paired fixture

LaTeX Article — Digital Filters Primer (.tex)

SAMPLE LaTeX article “Digital Filters Primer” with abstract, equation, and \cite to a twin .bib.

File: TEX · Latex Bib
Use case: Editor testingEncoding detection· Paired fixture

HL7 v2 — ADT-A03 SAMPLE

Short synthetic HL7 v2 ADT-A03 message — fictional SAMPLE demographics for parser tests.

File: HL7 · Hl7 Edi
Use case: Encoding detectionEditor testing· Conversion set

HL7 v2 — ORM-O01 SAMPLE

Short synthetic HL7 v2 ORM-O01 message — fictional SAMPLE demographics for parser tests.

File: HL7 · Hl7 Edi
Use case: Encoding detectionEditor testing· Conversion set

HL7 v2 — ORU-R01 SAMPLE

Short synthetic HL7 v2 ORU-R01 message — fictional SAMPLE demographics for parser tests.

File: HL7 · Hl7 Edi
Use case: Encoding detectionEditor testing· Conversion set

HL7 v2 — SIU-S12 SAMPLE

Short synthetic HL7 v2 SIU-S12 message — fictional SAMPLE demographics for parser tests.

File: HL7 · Hl7 Edi
Use case: Encoding detectionEditor testing· Conversion set

X12 EDI 855 — SAMPLE

Short ANSI X12 855 SAMPLE transaction for EDI parser / translator tests.

File: EDI · Hl7 Edi
Use case: Encoding detectionEditor testing· Conversion set

X12 EDI 856 — SAMPLE

Short ANSI X12 856 SAMPLE transaction for EDI parser / translator tests.

File: EDI · Hl7 Edi
Use case: Encoding detectionEditor testing· Conversion set

X12 EDI 997 — SAMPLE

Short ANSI X12 997 SAMPLE transaction for EDI parser / translator tests.

File: EDI · Hl7 Edi
Use case: Encoding detectionEditor testing· Conversion set

X12 EDI 940 — SAMPLE

Short ANSI X12 940 SAMPLE transaction for EDI parser / translator tests.

File: EDI · Hl7 Edi
Use case: Encoding detectionEditor testing· Conversion set

X12 EDI 204 — SAMPLE

Short ANSI X12 204 SAMPLE transaction for EDI parser / translator tests.

File: EDI · Hl7 Edi
Use case: Encoding detectionEditor testing· Conversion set

X12 EDI 214 — SAMPLE

Short ANSI X12 214 SAMPLE transaction for EDI parser / translator tests.

File: EDI · Hl7 Edi
Use case: Encoding detectionEditor testing· Conversion set

Latin-1 Encoded CSV

A CSV encoded in Latin-1 (ISO-8859-1) with accented names — for testing encoding detection and mis-decoding (it will look wrong if read as UTF-8).

File: CSV · CSV · 3 rows
Use case: CSV parsingEncoding detection

CSV — UTF-8 with BOM

A CSV prefixed with a UTF-8 BOM (EF BB BF) and accented / CJK cells — for testing BOM-aware importers.

File: CSV · Encodings · 3 rows
Use case: CSV parsingEncoding detection+1

CSV — UTF-16 LE with BOM

The same three data rows as UTF-16 little-endian with a BOM — wide-character CSV decoding fixture.

File: CSV · Encodings · 3 rows
Use case: CSV parsingEncoding detection

CSV — UTF-16 BE with BOM

UTF-16 big-endian CSV with BOM — for byte-order detection in tabular importers.

File: CSV · Encodings · 3 rows
Use case: CSV parsingEncoding detection

CSV — Windows-1252 (CP1252)

A CP1252 CSV using the 0x80–0x9F range (smart quotes, euro, bullet) that Latin-1 misreads.

File: CSV · Encodings · 2 rows
Use case: CSV parsingEncoding detection

CSV — Shift-JIS Japanese

A Shift-JIS encoded Japanese CSV — for CJK charset detection and Shift-JIS→UTF-8 conversion in importers.

File: CSV · Encodings · 2 rows
Use case: CSV parsingEncoding detection+1

Fixed-Width Positions File (TXT)

A classic fixed-width text extract with documented column positions — for COBOL-style / mainframe importer tests.

File: TXT · Encodings · 3 rows
Use case: CSV parsingData import+1

CSV — Mixed CRLF and LF

A CSV that mixes CRLF and LF row endings within one file — newline normalisation fixture.

File: CSV · Encodings · 3 rows
Use case: CSV parsingEncoding detection

CSV — ISO-8859-1 (Latin-1)

A Latin-1 CSV with high-bit accented characters — for legacy 8-bit charset detection.

File: CSV · Encodings · 2 rows
Use case: CSV parsingEncoding detection

ZIP - UTF-8 Name Flag Set

Member names stored as UTF-8 with general-purpose bit 11 (the language-encoding flag) set, which is the modern, unambiguous way to carry a non-ASCII filename in a ZIP. Its CP437 twin encodes the same archive the legacy way, so a reader's encoding heuristic can be compared against a case where the answer is declared.

File: ZIP · Zip Encoding · 3 members
Use case: Conversion testingEncoding detection· Paired fixture

ZIP - CP437 Legacy Name Encoding

The legacy twin: names encoded in IBM CP437 with the language-encoding flag clear, which is what the ZIP spec says an un-flagged name means. Decoding these bytes as UTF-8 produces mojibake or an outright decode error, which is exactly the bug this file is for.

File: ZIP · Zip Encoding · 3 members
Use case: Conversion testingEncoding detection· Paired fixture

ZIP - Info-ZIP Unicode Path Extra Field

The third way a ZIP carries a non-ASCII name: an ASCII-safe name in the header plus an Info-ZIP Unicode Path extra field (0x7075) holding the real UTF-8 name and a CRC32 of the header name. A reader must prefer the extra field, but only while that CRC still matches the header name it was computed from.

File: ZIP · Zip Encoding · 3 members
Use case: Conversion testingEncoding detection+1· Conversion set

TAR - PAX UTF-8 Member Names

PAX is the only tar variant that says what encoding its names are in: extended-header records are UTF-8 by definition. These three members carry accented Spanish and Japanese path components, so a reader that applies a locale-dependent guess instead of trusting the format produces mojibake on exactly this file.

File: TAR · Tar Format · 3 members
Use case: Conversion testingEncoding detection· Conversion set

Plain-Text Chapters (TXT)

A plain-text multi-chapter SAMPLE extract — for ebook converters that accept .txt sources.

File: TXT · Plain · UTF-8
Use case: Encoding detectionEditor testing

EPUB 3 - Metadata with Diacritics and a Combining Mark

A package document whose title and creator carry precomposed accents, a combining ring above a bare letter, and a typographic apostrophe. For testing normalisation, sorting and filename derivation - the combining mark is the one that breaks naive length and comparison code.

File: EPUB · Metadata Encoding
Use case: Encoding detectionMetadata testing· Conversion set

EPUB 3 - Metadata Written as Numeric Character References

Every non-ASCII character in the metadata is written as a hexadecimal numeric character reference, so the package document is pure ASCII on disk while the title is Han and Cyrillic once parsed. For testing tools that read metadata with a regex instead of an XML parser.

File: EPUB · Metadata Encoding
Use case: Encoding detectionMetadata testing· Conversion set

EPUB 3 - UTF-16 Package Document

The package document is encoded as UTF-16 little-endian with a byte order mark while the content documents stay UTF-8 - a combination EPUB permits and almost nothing tests. For finding the parser that opens the OPF as UTF-8 and sees a file full of null bytes.

File: EPUB · Metadata Encoding
Use case: Encoding detectionMetadata testing+1· Conversion set

EPUB 3 - Metadata with Astral-Plane Characters

A title containing two characters above the Basic Multilingual Plane - a blue book and a musical clef - plus a Japanese description. Anything that counts characters as UTF-16 code units, or truncates a title to a byte length, splits a surrogate pair here.

File: EPUB · Metadata Encoding
Use case: Encoding detectionMetadata testing+1· Conversion set

EPUB 3 - UTF-8 BOM on Every XML Part

The package document, the navigation document and the chapter each begin with a UTF-8 byte order mark before the XML declaration. Legal, and the classic reason a strict parser reports content before the prolog on a file that looks perfectly fine in an editor.

File: EPUB · Metadata Encoding
Use case: Encoding detectionMetadata testing+1· Conversion set

FB2 - Declared windows-1251 Encoding (Cyrillic)

A Cyrillic FictionBook stored in windows-1251 and declaring that encoding in its XML declaration - the single-byte legacy encoding a large share of real FB2 files still use. For testing importers that assume every XML file is UTF-8 and produce mojibake instead of an error.

File: FB2 · Fb2 · windows-1251
Use case: Encoding detectionConversion testing· Conversion set

EML — UTF-8 Encoded Subject

An email whose Subject uses RFC 2047 UTF-8 encoded-words (café / crème) — for header decoding tests.

File: EML · Headers
Use case: Email parsingEncoding detection+1

EML — UTF-8 Filename Attachment

An attachment whose filename uses RFC 2231 UTF-8 encoding (résumé) — for MIME filename decoders.

File: EML · Mime
Use case: Email parsingEncoding detection+1

EML — Quoted-Printable: Accented UTF-8 Body

A quoted-printable text/plain message in utf-8 whose body carries accented French text, guillemets, an em dash and a euro sign. It is the exact twin of the base64 message beside it: both decode to the same 247 octets, so a decoder can be diffed against a known-equal pair.

File: EML · Mime
Use case: Email parsingEncoding detection+1· Paired fixture

EML — Base64: Accented UTF-8 Body

A base64 text/plain message in utf-8 carrying the identical body to the quoted-printable twin beside it. Base64 is opaque to whitespace and line-start characters, so it is the reference side of the pair when a QP decoder is suspect.

File: EML · Mime
Use case: Email parsingEncoding detection+1· Paired fixture

EML — Quoted-Printable: Trailing Whitespace

A quoted-printable text/plain message in utf-8 whose body ends lines with spaces and tabs that quoted-printable must encode as =20 and =09. It is the exact twin of the base64 message beside it: both decode to the same 193 octets, so a decoder can be diffed against a known-equal pair.

File: EML · Mime
Use case: Email parsingEncoding detection+1· Paired fixture

EML — Base64: Trailing Whitespace

A base64 text/plain message in utf-8 carrying the identical body to the quoted-printable twin beside it. Base64 is opaque to whitespace and line-start characters, so it is the reference side of the pair when a QP decoder is suspect.

File: EML · Mime
Use case: Email parsingEncoding detection+1· Paired fixture

EML — Quoted-Printable: Soft Line Breaks

A quoted-printable text/plain message in utf-8 whose body holds a single line far past 76 columns, forcing quoted-printable soft breaks. It is the exact twin of the base64 message beside it: both decode to the same 451 octets, so a decoder can be diffed against a known-equal pair.

File: EML · Mime
Use case: Email parsingEncoding detection+1· Paired fixture

EML — Base64: Soft Line Breaks

A base64 text/plain message in utf-8 carrying the identical body to the quoted-printable twin beside it. Base64 is opaque to whitespace and line-start characters, so it is the reference side of the pair when a QP decoder is suspect.

File: EML · Mime
Use case: Email parsingEncoding detection+1· Paired fixture

EML — Quoted-Printable: ISO-8859-1 Body

A quoted-printable text/plain message in iso-8859-1 whose body is single-byte ISO-8859-1 rather than UTF-8, so each umlaut is one octet. It is the exact twin of the base64 message beside it: both decode to the same 176 octets, so a decoder can be diffed against a known-equal pair.

File: EML · Mime
Use case: Email parsingEncoding detection+1· Paired fixture

EML — Base64: ISO-8859-1 Body

A base64 text/plain message in iso-8859-1 carrying the identical body to the quoted-printable twin beside it. Base64 is opaque to whitespace and line-start characters, so it is the reference side of the pair when a QP decoder is suspect.

File: EML · Mime
Use case: Email parsingEncoding detection+1· Paired fixture

EML — Quoted-Printable: From-Line and Lone Dot

A quoted-printable text/plain message in utf-8 whose body starts a line with "From " and holds a lone "." line, which quoted-printable escapes as =46rom and =2E. It is the exact twin of the base64 message beside it: both decode to the same 219 octets, so a decoder can be diffed against a known-equal pair.

File: EML · Mime
Use case: Email parsingEncoding detection+1· Paired fixture

EML — Base64: From-Line and Lone Dot

A base64 text/plain message in utf-8 carrying the identical body to the quoted-printable twin beside it. Base64 is opaque to whitespace and line-start characters, so it is the reference side of the pair when a QP decoder is suspect.

File: EML · Mime
Use case: Email parsingEncoding detection+1· Paired fixture

EML — RFC 2047 Subject: UTF-8 'B' Encoding

A Subject header carrying accented Latin text and an emoji as a single UTF-8 base64 encoded-word. Its Q-encoded twin decodes to the identical string, so the two together isolate the encoding from the charset.

File: EML · Headers · B (base64)
Use case: Email parsingEncoding detection+1· Paired fixture

EML — RFC 2047 Subject: UTF-8 'Q' Encoding

The same Subject as the UTF-8 'B' twin, written with 'Q' encoding instead: underscores stand for spaces and every non-token octet is an =XX escape. A decoder that forgets the underscore rule produces visibly different text from its twin.

File: EML · Headers · Q (quoted-printable-like)
Use case: Email parsingEncoding detection+1· Paired fixture

EML — RFC 2047 Subject: ISO-8859-1 'Q' Encoding

A German Subject encoded as ISO-8859-1 'Q', the shape most legacy mail actually uses. Each umlaut is one =XX escape, so a decoder that assumes UTF-8 produces mojibake rather than a clean error.

File: EML · Headers · Q
Use case: Email parsingEncoding detection+1· Paired fixture

EML — RFC 2047 Subject: ISO-8859-1 'B' Encoding

The ISO-8859-1 Subject again, base64-encoded instead of Q-encoded. Base64 hides the charset entirely, so this is the fixture that catches a decoder guessing the charset from the octets instead of reading the encoded-word's charset token.

File: EML · Headers · B (base64)
Use case: Email parsingEncoding detection+1· Paired fixture

EML — RFC 2047 Subject: Shift_JIS 'B' Encoding

A Japanese Subject as a Shift_JIS base64 encoded-word. Shift_JIS second bytes overlap ASCII punctuation values, so a decoder that scans the decoded octets for delimiters before converting the charset splits the string in the wrong place.

File: EML · Headers · B (base64)
Use case: Email parsingEncoding detection+1· Conversion set

EML — RFC 2047 Subject: KOI8-R 'B' Encoding

A Russian Subject as a KOI8-R base64 encoded-word. KOI8-R orders Cyrillic letters by Latin transliteration rather than alphabetically, so a decoder that substitutes any other Cyrillic codepage returns readable-looking but wrong text.

File: EML · Headers · B (base64)
Use case: Email parsingEncoding detection+1· Conversion set

EML — RFC 2047 Subject Mixing Three Charsets

A single Subject built from three encoded-words in three charsets and two encodings. RFC 2047 allows this, and it is what happens when a subject is quoted through several mail systems, so each word has to be decoded on its own terms.

File: EML · Headers
Use case: Email parsingEncoding detection+1· Conversion set

EML — Adjacent Encoded-Words (Separator Must Disappear)

A Subject split mid-word across two adjacent encoded-words. RFC 2047 requires the linear whitespace between them to be discarded, so the correct result is one word; a decoder that keeps the space renders a split that reads as a typo.

File: EML · Headers
Use case: Email parsingEncoding detection+1· Conversion set

EML — Encoded-Word Subject Folded Over Four Lines

A Subject folded across four physical lines, one encoded-word per line, which is the shape RFC 2047 prescribes for long international headers. Because the fold whitespace is discarded on decode, each continuation word carries its own leading space inside the encoded-word — omit that and the subject decodes run-together.

File: EML · Headers
Use case: Email parsingEncoding detection+1· Conversion set

EML — Encoded-Word Longer Than the 75-Character Limit

One unbroken encoded-word of 148 characters, well past the 75-character ceiling RFC 2047 sets. Real senders emit these, and a decoder should still recover the whole word rather than truncating it at 75 or rejecting the header.

File: EML · Headers · B (base64)
Use case: Email parsingEncoding detection+1· Conversion set

EML — Encoded-Words in Display Names and a Filename

Encoded-words used everywhere they turn up in practice: both display names, the Subject, and — against the spec but very common — inside the quoted filename parameter, where RFC 2231 is the conformant mechanism. A tolerant parser decodes all four.

File: EML · Headers
Use case: Email parsingEncoding detection+1· Conversion set

EML — RFC 2231 Continuation Filename With size and creation-date

The conformant answer to non-ASCII filenames: a filename split into three numbered RFC 2231 segments with a charset and a language tag, plus size and creation-date parameters. Parsers commonly handle filename*= but not the numbered continuation form.

File: EML · Mime · de
Use case: Email parsingEncoding detection+1· Conversion set

MBOX — Four Charsets and Both Transfer Encodings

One mailbox whose four messages each use a different charset and alternate between quoted-printable and base64, with RFC 2047 subjects to match. The file itself is LF-stored while the encoded payloads decode to CRLF text — the split every importer has to handle.

File: MBOX · Mailbox
Use case: Email parsingEncoding detection+1· Conversion set

Gettext PO — French

A French (fr) gettext PO catalog with seven UI strings — for i18n toolchain tests.

File: PO · Gettext
Use case: InternationalizationEncoding detection· Paired fixture

Gettext PO — German

A German (de) gettext PO catalog with seven UI strings — for i18n toolchain tests.

File: PO · Gettext
Use case: InternationalizationEncoding detection· Paired fixture

Gettext PO — Portuguese (Brazil)

A Portuguese (Brazil) (pt-BR) gettext PO catalog with seven UI strings — for i18n toolchain tests.

File: PO · Gettext
Use case: InternationalizationEncoding detection· Paired fixture

Gettext PO — Korean

A Korean (ko) gettext PO catalog with seven UI strings — for i18n toolchain tests.

File: PO · Gettext
Use case: InternationalizationEncoding detection· Paired fixture

Fluent (.ftl) — English

Mozilla Fluent SAMPLE catalog (English) with placeholders and plural select — for Fluent parsers and CAT tools.

File: FTL · Fluent
Use case: InternationalizationLocalization catalogs+1· Conversion set

Fluent (.ftl) — Spanish

Mozilla Fluent SAMPLE catalog (Spanish) with placeholders and plural select — for Fluent parsers and CAT tools.

File: FTL · Fluent
Use case: InternationalizationLocalization catalogs+1· Conversion set

Fluent (.ftl) — French

Mozilla Fluent SAMPLE catalog (French) with placeholders and plural select — for Fluent parsers and CAT tools.

File: FTL · Fluent
Use case: InternationalizationLocalization catalogs+1· Conversion set

Fluent (.ftl) — Arabic RTL

Mozilla Fluent SAMPLE catalog (Arabic RTL) with placeholders and plural select — for Fluent parsers and CAT tools.

File: FTL · Fluent
Use case: InternationalizationLocalization catalogs+1· Conversion set

Fluent (.ftl) — Hebrew RTL

Mozilla Fluent SAMPLE catalog (Hebrew RTL) with placeholders and plural select — for Fluent parsers and CAT tools.

File: FTL · Fluent
Use case: InternationalizationLocalization catalogs+1· Conversion set

Fluent (.ftl) — English US

Mozilla Fluent SAMPLE catalog (English US) with placeholders and plural select — for Fluent parsers and CAT tools.

File: FTL · Fluent
Use case: InternationalizationLocalization catalogs+1· Conversion set

ICU MessageFormat JSON — English

ICU MessageFormat SAMPLE JSON (English) with plural/select patterns for i18n runtimes.

File: JSON · Icu
Use case: InternationalizationLocalization catalogs+1· Conversion set

ICU MessageFormat JSON — Spanish

ICU MessageFormat SAMPLE JSON (Spanish) with plural/select patterns for i18n runtimes.

File: JSON · Icu
Use case: InternationalizationLocalization catalogs+1· Conversion set

ICU MessageFormat JSON — French

ICU MessageFormat SAMPLE JSON (French) with plural/select patterns for i18n runtimes.

File: JSON · Icu
Use case: InternationalizationLocalization catalogs+1· Conversion set

ICU MessageFormat JSON — Arabic

ICU MessageFormat SAMPLE JSON (Arabic) with plural/select patterns for i18n runtimes.

File: JSON · Icu
Use case: InternationalizationLocalization catalogs+1· Conversion set

ICU MessageFormat JSON — Hebrew

ICU MessageFormat SAMPLE JSON (Hebrew) with plural/select patterns for i18n runtimes.

File: JSON · Icu
Use case: InternationalizationLocalization catalogs+1· Conversion set

ICU MessageFormat JSON — German

ICU MessageFormat SAMPLE JSON (German) with plural/select patterns for i18n runtimes.

File: JSON · Icu
Use case: InternationalizationLocalization catalogs+1· Conversion set

ICU MessageFormat JSON — Japanese

ICU MessageFormat SAMPLE JSON (Japanese) with plural/select patterns for i18n runtimes.

File: JSON · Icu
Use case: InternationalizationLocalization catalogs+1· Conversion set

ICU MessageFormat JSON — Chinese

ICU MessageFormat SAMPLE JSON (Chinese) with plural/select patterns for i18n runtimes.

File: JSON · Icu
Use case: InternationalizationLocalization catalogs+1· Conversion set

ICU Plural + Selectordinal — English

English ICU plural and selectordinal SAMPLE catalogue for plural-rule engines.

File: JSON · Plural
Use case: InternationalizationLocalization catalogs+1· Conversion set

ICU Plural — Arabic (RTL)

Arabic RTL ICU plural SAMPLE covering zero/one/two/few/many/other categories.

File: JSON · Plural
Use case: InternationalizationLocalization catalogs+1· Conversion set

ICU Select Catalogue — English

ICU select SAMPLE for gender/status branching in message formatters.

File: JSON · Plural
Use case: InternationalizationLocalization catalogs+1· Conversion set

ICU Select — Hebrew (RTL)

Hebrew RTL ICU select SAMPLE for bidirectional UI string pipelines.

File: JSON · Plural
Use case: InternationalizationLocalization catalogs+1· Conversion set

RTL UI Pack — Arabic

Arabic RTL UI string pack SAMPLE for bidirectional layout and font-fallback tests.

File: JSON · Rtl
Use case: InternationalizationLocalization catalogs+1· Conversion set

RTL UI Pack — Hebrew

Hebrew RTL UI string pack SAMPLE for bidirectional layout and font-fallback tests.

File: JSON · Rtl
Use case: InternationalizationLocalization catalogs+1· Conversion set

RTL UI Pack — Arabic Egypt

Arabic Egypt RTL UI string pack SAMPLE for bidirectional layout and font-fallback tests.

File: JSON · Rtl
Use case: InternationalizationLocalization catalogs+1· Conversion set

RTL UI Pack — Hebrew Israel

Hebrew Israel RTL UI string pack SAMPLE for bidirectional layout and font-fallback tests.

File: JSON · Rtl
Use case: InternationalizationLocalization catalogs+1· Conversion set

RTL UI Pack — Persian

Persian RTL UI string pack SAMPLE for bidirectional layout and font-fallback tests.

File: JSON · Rtl
Use case: InternationalizationLocalization catalogs+1· Conversion set

RTL UI Pack — Urdu

Urdu RTL UI string pack SAMPLE for bidirectional layout and font-fallback tests.

File: JSON · Rtl
Use case: InternationalizationLocalization catalogs+1· Conversion set

Crowdin-Style Export — Spanish

Crowdin-shaped SAMPLE bilingual export JSON for localization TMS importers.

File: JSON · Crowdin · es
Use case: InternationalizationLocalization catalogs+1· Conversion set

Crowdin-Style Export — French

Crowdin-shaped SAMPLE French bilingual export for TMS round-trip tests.

File: JSON · Crowdin · fr
Use case: InternationalizationLocalization catalogs+1· Conversion set

Bilingual CSV — English→Spanish

Bilingual EN→ES CSV SAMPLE for spreadsheet-based localization workflows.

File: CSV · CSV · 4 rows
Use case: InternationalizationLocalization catalogs+1

Bilingual CSV — English→Arabic RTL

Bilingual EN→AR RTL CSV SAMPLE for spreadsheet CAT and RTL review tools.

File: CSV · CSV · 3 rows
Use case: InternationalizationLocalization catalogs+1

Multilingual CSV — EN/ES/FR/DE

Four-locale multilingual CSV SAMPLE for bulk translation import tests.

File: CSV · CSV · 3 rows
Use case: InternationalizationLocalization catalogs+1

Pseudolocalization Pack — en-XA

Pseudolocalization SAMPLE (bracket-wrapped) for i18n layout overflow testing.

File: JSON · Pseudo
Use case: InternationalizationLocalization catalogs+1

Java ResourceBundle .properties — English

A English Java ResourceBundle with MessageFormat patterns, a ChoiceFormat plural, positional arguments, escaped braces and apostrophes, a backslash line continuation, and non-ASCII carried as \uXXXX escapes because .properties is defined as ISO-8859-1. The bytes on disk are pure ASCII.

File: PROPERTIES · Icu · ISO-8859-1, non-ASCII written as \uXXXX escapes
Use case: InternationalizationLocalization catalogs+2· Conversion set

Java ResourceBundle .properties — German

A German Java ResourceBundle with MessageFormat patterns, a ChoiceFormat plural, positional arguments, escaped braces and apostrophes, a backslash line continuation, and non-ASCII carried as \uXXXX escapes because .properties is defined as ISO-8859-1. The bytes on disk are pure ASCII.

File: PROPERTIES · Icu · ISO-8859-1, non-ASCII written as \uXXXX escapes
Use case: InternationalizationLocalization catalogs+2· Conversion set

Apple .strings — UTF-16 LE with BOM (Japanese)

The encoding fixture the .strings format needs: a Japanese catalog written as UTF-16 Little Endian with a byte-order mark, which is what Xcode has historically produced and what a UTF-8-only reader turns into mojibake or a decode error. Also carries full-width punctuation and an ideographic space for width and line-breaking tests.

File: STRINGS · Apple · UTF-16 LE
Use case: InternationalizationEncoding detection+1· Conversion set

Unicode Bidi Controls — LRM, RLM, ALM, isolates and embeddings

A reference sheet in which each of the ten shipped bidi control characters appears literally between ASCII guards, with its code point, UTF-8 bytes and the job it does. The two override characters are named but deliberately absent: a bidi rendering fixture does not need to ship the Trojan Source vector.

File: TXT · Bidi · UTF-8
Use case: InternationalizationEncoding detection+1· Conversion set

Bidi — where a mark is actually required (Arabic)

Six Arabic sentences containing a Latin filename, a phone number, a version range, a mixed-script path, a percentage and a bracketed insertion — each shown first as a translator usually delivers it and then with the one invisible character that makes it render correctly. The two forms differ by exactly one code point.

File: TXT · Bidi · UTF-8
Use case: InternationalizationEncoding detection+1· Conversion set

Bidi — bracket mirroring in RTL paragraphs (Hebrew and Arabic)

Mirroring is a rendering property of the bidi algorithm, not a transformation of the text: a U+0028 LEFT PARENTHESIS inside an RTL run is DRAWN as ')' while the stored byte never changes. These Hebrew and Arabic lines make that testable, and list the neutral characters that look like they should mirror but do not.

File: TXT · Bidi · UTF-8
Use case: InternationalizationEncoding detection+1· Conversion set

Locale Number Formats — twelve locales (CSV)

The same number, 1234567.89, rendered for twelve locales, with the group and decimal separator that produced each one named by code point and present literally in the cell. Four of the separators are not ASCII — U+00A0, U+202F, U+2019 and U+066C — and ar-EG additionally switches the digits themselves.

File: CSV · Formatting · 12 rows
Use case: InternationalizationCSV parsing+1· Conversion set

Locale Number Formats — twelve locales with documented traps (JSON)

The structured twin of the number-format table, plus four documented traps: es-ES's minimumGroupingDigits=2 (which leaves a four-digit integer ungrouped), the four non-ASCII group separators, the arab numbering system's own digits, and the seven locales here whose decimal separator is a comma.

File: JSON · Formatting
Use case: InternationalizationJSON parsing+1· Conversion set

Locale Currency Formats — eleven locales (CSV)

12345.60 in each locale's own currency, with the fraction-digit count and the symbol placement that produced it. JPY takes zero decimals and rounds; six rows separate the amount from the symbol with U+00A0 rather than a plain space; and ar-EG puts the amount in Arabic-Indic digits.

File: CSV · Formatting · 11 rows
Use case: InternationalizationCSV parsing+1· Conversion set

Locale Currency Formats — minor units and invisible separators (JSON)

The structured currency table with the three traps spelled out: minor units belong to the CURRENCY not the locale (JPY 0, USD 2, KWD/BHD/JOD 3), the gap before a trailing symbol is U+00A0 in six of these locales, and CLDR's ar-EG pattern contains an invisible U+200F that breaks naive equality assertions.

File: JSON · Formatting
Use case: InternationalizationJSON parsing+1· Conversion set

Locale Separator and Digit Characters — literal specimens

Every separator, sign and digit set a locale-aware formatter has to survive, each present literally between ASCII guards: the no-break and narrow-no-break spaces, de-CH's U+2019 group separator, the Arabic decimal and thousands separators, the four numbering systems' digits, and CLDR's U+2212 MINUS SIGN, which is not the ASCII hyphen.

File: TXT · Formatting · UTF-8
Use case: InternationalizationEncoding detection+1

JUnit XML — Escaped Characters in Test Names

Test names containing &, <, >, quotes and an apostrophe, escaped as XML requires. Round-tripping this report through a converter is the fastest way to find double-escaping bugs that turn & into &amp; one hop at a time.

File: XML · Junit XML · UTF-8
Use case: Encoding detectionConversion testing+1· Conversion set

JUnit XML — Non-ASCII Test Names (UTF-8)

Test names in German, French, Japanese, Greek and Russian, stored as UTF-8 with no BOM and an explicit encoding declaration. A reporter that assumes the platform default encoding produces mojibake here rather than an error.

File: XML · Junit XML · UTF-8
Use case: Encoding detectionInternationalization+1· Conversion set

JUnit XML — Locale-Formatted and Exponent Durations

Durations written four different ways in one file: scientific notation, a comma decimal separator from a German-locale JVM, a bare integer, and a comma that could be either a decimal point or a thousands separator. A parser using a locale-sensitive number reader gets a different answer depending on where it runs.

File: XML · Junit XML · UTF-8
Use case: Error handlingConversion testing+1· Conversion set

Gherkin — French Keywords (# language: fr)

A feature written entirely in French keywords, declared by the # language: fr header that must be the first line of the file. Parsers that hardcode English keywords read this as a feature with no scenarios rather than reporting an error, so it fails silently.

File: FEATURE · Bdd · fr
Use case: InternationalizationCode parsing+1· Conversion set

Unified Diff - CRLF Line Endings Throughout

Byte-for-byte the same diff as its LF twin except that every line ends CR LF, which is what a diff produced or saved on Windows looks like. Readers that compare a hunk line against expected content without stripping the CR find that no line matches.

File: DIFF · Diffs · UTF-8
Use case: Encoding detectionVisual diff / regression+1· Paired fixture

Unified Diff - LF Line Endings Throughout

The LF half of the line-ending twin pair: identical text content to the CRLF fixture, differing only in the terminator bytes. Diff the two downloads to see nothing but line-ending changes, and use the pair to score end-of-line normalisation.

File: DIFF · Diffs · UTF-8
Use case: Encoding detectionVisual diff / regression+1· Paired fixture

Unified Diff - Line-Ending Conversion as Content Change

The file itself is LF-terminated, but every removed line carries a literal CR as its last character because the change under review is a CRLF-to-LF conversion. Renderers that do not show the CR display a hunk in which every removed and added line looks identical.

File: DIFF · Diffs · UTF-8
Use case: Encoding detectionVisual diff / regression+1

Unified Diff - Octal-Quoted Non-ASCII Paths

With git's default `core.quotepath`, a path containing non-ASCII bytes is wrapped in double quotes and each byte is written as a backslash-octal escape. A parser that takes the header text literally creates a directory called `caf\303\251` on disk.

File: DIFF · Diffs · UTF-8
Use case: Encoding detectionVisual diff / regression+1· Conversion set

Unified Diff - Raw UTF-8 Non-ASCII Paths

The same change with `core.quotepath=false`, so the path is written as raw UTF-8 and the header is not quoted. Compare with the quoted twin to confirm a parser resolves both spellings to the same file.

File: DIFF · Diffs · UTF-8
Use case: Encoding detectionVisual diff / regression+1· Conversion set

Git Patch - RFC 2047 Encoded-Word Subject and Author

Non-ASCII in the author name and the subject, so both are Q-encoded into `=?UTF-8?q?...?=` words and the subject is folded across two lines with a leading space. The body is left as raw UTF-8, which means one message needs two different decoders.

File: PATCH · Patches
Use case: Encoding detectionVisual diff / regression+1

Git Patch - CRLF Line Endings Throughout

The whole patch file uses CRLF terminators, as it would after a round trip through a Windows editor or a mail client. `git am` needs `--keep-cr` to be told the CRs belong to the patch rather than to the content, and the `-- ` signature line now ends with space-CR-LF.

File: PATCH · Patches · UTF-8
Use case: Encoding detectionVisual diff / regression+1· Paired fixture

Git Patch - LF Line Endings Throughout

The LF half of the patch twin pair, identical in text content to the CRLF fixture. Diff the two downloads to get a change that is invisible in every renderer and fatal to a byte comparison.

File: PATCH · Patches · UTF-8
Use case: Encoding detectionVisual diff / regression+1· Paired fixture

Gitattributes - End-of-Line Normalisation Rules

The attribute file that decides what happens to line endings on checkout: `text=auto` as the default, explicit `eol=lf` and `eol=crlf` overrides, the `binary` macro that expands to `-text -diff`, and one `-text` entry that is still given a textconv driver. This is the file whose absence causes the CRLF twins elsewhere in this category.

File: GITATTRIBUTES · Repo Config · UTF-8
Use case: Config parsingEncoding detection+1

Prometheus Exposition — Label Value Escaping Edge Cases (prom)

Ten series whose label values contain the characters that break naive line splitting — escaped quotes and backslashes, an escaped newline, non-ASCII text, braces, commas, equals signs, a leading hash and significant whitespace. The exposition format defines exactly three escapes and this file uses all of them.

File: PROM · Metrics
Use case: ObservabilityEncoding detection+1· Conversion set

Prometheus Exposition — UTF-8 Quoted Metric and Label Names (prom)

Dotted OpenTelemetry-style metric and label names written with the quoted-name syntax that Prometheus 3 accepts, mixed in one document with a legacy underscore-named family. The fixture for parsers that still assume every name matches [a-zA-Z_][a-zA-Z0-9_]*.

File: PROM · Metrics
Use case: ObservabilityEncoding detection+1· Conversion set

Structured Log — Ten Timestamp Formats, One Instant (jsonl)

The same instant written ten ways — RFC 3339 at three precisions and with a non-UTC offset, epoch seconds as integer and float, epoch milliseconds and nanoseconds, Common Log Format and the log4j comma-decimal form. What a timestamp autodetector must resolve to one moment.

File: JSONL · Logs
Use case: ObservabilityLog parsing+1· Conversion set

Structured Log — Unicode, RTL, Emoji and Control Characters (jsonl)

Log messages in Latin, Japanese and Arabic scripts, an emoji flag and a zero-width-joiner family, NFC and NFD forms of the same accented letter, and escaped tab, newline and carriage return. Everything that makes a log line's byte length and its display width disagree.

File: JSONL · Logs · UTF-8, unescaped
Use case: ObservabilityLog parsing+1· Conversion set

Structured Log — Lone Surrogate Escapes, Intentionally Invalid (jsonl)

Two records containing unpaired \ud800 and \udfff escapes between three well-formed ones, plus a correct surrogate pair for comparison. Intentionally invalid: the escapes are syntactically legal JSON but cannot be encoded as UTF-8, which is where a re-serialising pipeline breaks.

File: JSONL · Logs
Use case: ObservabilityEncoding detection+1· Conversion set

Plain-Text Log — ANSI Colour Codes in the Stream (log)

A developer-mode log where the level and service are wrapped in ANSI colour codes, ending with one uncoloured line. Colour codes sit inside the field a parser wants to read, so level extraction fails unless the sequences are stripped first — the classic symptom of a container run without a TTY check.

File: LOG · Logs
Use case: ObservabilityLog parsing+1· Conversion set

Plain-Text Log — Mixed CRLF and LF Line Endings (log)

One log file written by two agents, four lines ending CRLF and three LF, with one line carrying trailing spaces before its break. Splitting on \n alone leaves a stray carriage return at the end of four fields, which is how a level or status ends up with an invisible character attached.

File: LOG · Logs
Use case: ObservabilityLog parsing+1· Conversion set

Plain-Text Log — NUL, Control Bytes and Invalid UTF-8 (log)

Five log lines carrying a NUL byte, bell, backspace, vertical tab and form feed, plus one 0xFF byte that is not valid UTF-8 — the debris that arrives when binary data reaches a log field. Deliberately contains no terminal-escape sequences, only inert control bytes.

File: LOG · Logs
Use case: ObservabilityLog parsing+1· Conversion set

logfmt — Quoting, Escaping and Bare-Key Edge Cases (log)

logfmt lines built to break naive splitting on spaces and equals signs: a value containing an equals sign, escaped quotes, a trailing backslash before the closing quote, a bare key with no value, duplicate keys, non-ASCII values and one unterminated quote followed by a clean line.

File: LOG · Logs
Use case: ObservabilityLog parsing+1· Conversion set

txt

618 B

Profile — Demangled Symbols That Break the Folded Format (txt)

Demangled C++ templates, Rust trait impls, Java generics, lambdas and unresolved hex addresses in the folded format — including one symbol containing a semicolon, which the format has no way to escape. That line is genuinely ambiguous, and how a parser handles it is the point.

File: TXT · Profiles
Use case: ObservabilityLog parsing+1· Conversion set

CycloneDX SBOM With Unicode Metadata (Edge Case)

A CycloneDX SBOM whose author names and properties contain accented Latin, CJK, right-to-left Hebrew, emoji and a deliberately long property value — for testing encoding handling and field-width assumptions. Every package, version, hash and licence is fictional — the tree describes nothing real.

File: JSON · Sbom · UTF-8 (no BOM)
Use case: JSON parsingEncoding detection+1· Conversion set

GeoJSON — Non-ASCII Property Values

Four features whose labels are written in Latin with diacritics, katakana, right-to-left Arabic, and a decomposed combining sequence — all stored as raw UTF-8 rather than \u escapes. Shapefile DBF export is where these usually turn into question marks.

File: GEOJSON · Geojson · UTF-8
Use case: GeospatialEncoding detection+1· Conversion set

NMEA 0183 — LF Line Endings Instead of CRLF

The same sentences terminated with a bare LF rather than the CR LF the standard mandates — what you get after a log passes through a text editor or a Unix pipeline. Parsers that strip only "\r\n" leave a stray character on every line and then fail the checksum.

File: NMEA · Nmea · ASCII
Use case: GeospatialError handling+1· Conversion set

Shapefile — Code Page Sidecar (.cpg, UTF-8)

A one-line sidecar naming the encoding of the .dbf. Without it a reader has to guess — usually cp1252 — and every non-ASCII attribute value comes back as mojibake, which is the single most common shapefile data-loss bug.

File: CPG · Shapefile
Use case: GeospatialEncoding detection+1· Conversion set

Shapefile DBF — Accented Attributes in UTF-8

The same four accented attribute rows written in UTF-8. Both files are exactly the same size because DBF fields are fixed-width in bytes, not characters — so the UTF-8 table fits fewer characters per field, and a reader that guesses the encoding produces mojibake rather than an obvious failure.

File: DBF · Shapefile · 4 records
Use case: GeospatialEncoding detection+1· Conversion set

Shapefile Code Page — UTF-8 Declaration

The sidecar that declares `attributes-utf8.dbf` as UTF-8. Note that the DBF also carries a language-driver byte in its header, and the two can disagree — which is exactly the ambiguity a reader has to resolve and document.

File: CPG · Shapefile
Use case: GeospatialEncoding detection+1· Conversion set

Shapefile DBF — Accented Attributes in CP1252

The same four accented attribute rows written in CP1252. Both files are exactly the same size because DBF fields are fixed-width in bytes, not characters — so the UTF-8 table fits fewer characters per field, and a reader that guesses the encoding produces mojibake rather than an obvious failure.

File: DBF · Shapefile · 4 records
Use case: GeospatialEncoding detection+1· Conversion set

Shapefile Code Page — ISO-8859-1 Declaration

The sidecar that declares `attributes-cp1252.dbf` as ISO-8859-1. Note that the DBF also carries a language-driver byte in its header, and the two can disagree — which is exactly the ambiguity a reader has to resolve and document.

File: CPG · Shapefile
Use case: GeospatialEncoding detection+1· Conversion set

WKB — Hex Strings in Both Byte Orders

The same point encoded both ways, plus a polygon, as uppercase hex — the form WKB takes when it travels through a text column or a SQL console. The byte-order flag is the first byte of each string, so the two point encodings differ everywhere after it.

File: TXT · Wkt Wkb · 3 records
Use case: GeospatialSerialization testing+1· Conversion set

HDF5 Strings — Fixed, Variable-Length and UTF-8 (.h5)

Fixed-width byte strings, variable-length UTF-8 strings and UTF-8 attribute text in one file, including Greek, CJK and combining diacritics. HDF5 hands fixed-width strings back as padded bytes and variable-length ones as decoded text, and conflating the two is where string handling usually breaks.

File: H5 · Hdf5 · UTF-8
Use case: Scientific dataSerialization testing+1· Conversion set

NumPy .npy Format Version 3.0 — UTF-8 Field Names (.npy)

A structured array whose field names use Greek and CJK characters, which is the only reason format version 3.0 exists: its header is UTF-8 where 1.0 and 2.0 are latin-1. A parser that decodes the header as latin-1 mangles all three names.

File: NPY · Arrays · 5 records
Use case: Scientific dataSerialization testing+1· Conversion set

SI Unit Symbols in UTF-8 — Look-Alike Codepoints (.csv)

Eight measurements whose unit symbols use the codepoints that have Unicode look-alikes: MICRO SIGN against GREEK MU, OHM SIGN against GREEK OMEGA, ANGSTROM SIGN against A-with-ring. Each row also carries an ASCII fallback, so a normalisation bug shows up as a column mismatch rather than as an invisible change.

File: CSV · Measurements · 8 rows
Use case: Scientific dataEncoding detection+1· Conversion set

GitHub Actions on: Key YAML Boolean Trap

The workflow file that exposes the YAML 1.1 boolean resolver: a bare `on` key becomes True in PyYAML, SnakeYAML and Psych, so a round-trip through those loaders loses the trigger block. The env values repeat the trap with NO, yes and off alongside a quoted control.

File: YML · Github Actions
Use case: Config parsingEncoding detection+1

GitLab CI Anchors and Extends

The two GitLab inheritance mechanisms in one file: YAML anchors with merge keys, which the loader resolves before GitLab sees the document, and `extends`, which GitLab resolves afterwards with a deep merge. Hidden .job keys carry both.

File: YML · Gitlab Ci
Use case: Config parsingEncoding detection+1

GitLab CI !reference Custom YAML Tag

GitLab's `!reference` custom YAML tag used three ways: inside a script list, as a whole after_script value, and as a whole rules value. A stock YAML 1.2 loader has no constructor for it and raises; GitLab's loader resolves each key path.

File: YML · Gitlab Ci
Use case: Config parsingEncoding detection+1

Docker Compose Anchors and x- Extension Fields

Compose with three x- extension fields carrying YAML anchors that are merged into services. The trap is ordering: a tool that strips x- keys before parsing the YAML destroys the anchors and the file stops resolving.

File: YAML · Docker
Use case: Config parsingEncoding detection+1

YAML Anchors and Aliases

Anchors and aliases across mapping, sequence and scalar nodes, including an anchor nested inside another anchored node. The point most tooling misses: an alias is a reference to the same node, so a shallow-loading parser can share mutable state between jobs.

File: YAML · YAML Edge Cases
Use case: Config parsingEncoding detection+1

YAML Merge Keys and Precedence

Merge keys with their full precedence rules: local keys beat merged ones, and in a merge sequence the earlier alias wins. The file publishes the expected merged values, and a strict YAML 1.2 loader produces none of them because 1.2 dropped << from the core schema.

File: YAML · YAML Edge Cases
Use case: Config parsingEncoding detection+1

YAML Block Scalars and Chomping Indicators

Every block-scalar variation in one file: literal and folded styles, all three chomping indicators, an explicit indentation indicator, a folded block with a paragraph break, and an embedded shell-shaped script whose own indentation must survive.

File: YAML · YAML Edge Cases
Use case: Config parsingEncoding detection+1

YAML Norway Problem (Boolean Coercion)

The Norway problem in full: eleven bare words that a YAML 1.1 resolver turns into booleans, a matching quoted control group that survives, and a country-code list where position two silently becomes false. The definitive fixture for resolver-version behaviour.

File: YAML · YAML Edge Cases
Use case: Config parsingEncoding detection+1

YAML Implicit Typing Traps

Twenty-two unquoted values whose type depends entirely on the resolver. The worst is the leading zero: 0755 is 493 under YAML 1.1 and 755 under YAML 1.2, so both resolvers return a number and they return different ones. Also covers base-60 times, a version that loses its trailing zero, an integer past IEEE-754 precision, dates, and .inf / .nan.

File: YAML · YAML Edge Cases
Use case: Config parsingEncoding detection+1

YAML Duplicate Keys

Duplicate keys at three nesting levels, including a duplicated top-level sequence. The spec forbids them; most loaders keep the last silently, a few keep the first, and strict linters reject the document. The file publishes the last-wins answer.

File: YAML · YAML Edge Cases
Use case: Config parsingEncoding detection+1

YAML Multi-Document Stream

A five-document stream with explicit end markers, a comment-only document that loads as null, and a bare sequence as a whole document. The single-document API returns only the first, which is how multi-object manifests silently lose objects.

File: YAML · YAML Edge Cases
Use case: Config parsingEncoding detection+1

YAML Null and Empty Values

Five spellings of null against the things routinely confused with it: empty strings, empty collections, and a key written with no value at all. Includes a sequence containing a hole, an empty string and two nulls in a row.

File: YAML · YAML Edge Cases
Use case: Config parsingEncoding detection+1

YAML Quoting Styles and Escapes

All three scalar quoting styles side by side: plain scalars and what they cannot contain, single quotes where backslashes stay literal and '' means one quote, and double quotes as the only style that processes \t, \n and \uXXXX escapes.

File: YAML · YAML Edge Cases
Use case: Config parsingEncoding detection+1

YAML Flow and Block Styles

Flow (JSON-like) and block collections expressing the same structures, nested inside one another in both directions, plus a flow mapping wrapped across lines and a line of strict JSON — which is valid YAML, and a useful check on a parser's JSON-subset claim.

File: YAML · YAML Edge Cases
Use case: Config parsingEncoding detection+1

YAML Indentation Variants

The indentation styles that all parse identically and that formatters fight over: sequences flush with their key versus indented under it, two-space against four-space maps, and deliberately irregular but legal nesting. For testing formatters and idempotency.

File: YAML · YAML Edge Cases
Use case: Config parsingEncoding detection+1

YAML Non-ASCII Keys and Values

Non-ASCII keys and values across Latin, Cyrillic, Arabic, CJK and emoji, plus a key containing a zero-width space and a value distinguishing a combining acute from the precomposed character. Written as UTF-8 with no BOM.

File: YAML · YAML Edge Cases · UTF-8, no BOM
Use case: Config parsingEncoding detection+1

YAML with CRLF Line Endings

A YAML file written with CRLF line endings, which the spec accepts as a line break. A parser that splits on \n alone leaves a stray carriage return at the end of every plain scalar, so "build" becomes "build\r" and equality checks quietly fail.

File: YAML · YAML Edge Cases · UTF-8, no BOM
Use case: Config parsingEncoding detection+1

YAML with a UTF-8 Byte Order Mark

A YAML file beginning with a UTF-8 byte order mark, which the spec permits at the start of a stream. A parser that does not strip it reads the first key as \ufeffname, so the lookup misses and the document appears to be missing its name field.

File: YAML · YAML Edge Cases · UTF-8 with BOM
Use case: Config parsingEncoding detection+1

YAML Bounded Anchor Reuse

Nested anchor reuse kept deliberately small: two anchors, six references, thirty-one expanded nodes. It is here to test alias resolution and expansion accounting on a safe input, and is explicitly not a billion-laughs expansion bomb.

File: YAML · YAML Edge Cases
Use case: Config parsingEncoding detection+1

YAML Explicit and Local Tags

Explicit tags across the standard set — !!str, !!float, !!int, !!bool, !!null, !!binary, !!timestamp, !!omap, !!set — alongside two application-local ! tags. CI dialects use local tags in the wild, so a pipeline parser has to decide whether to reject, ignore, or resolve them.

File: YAML · YAML Edge Cases
Use case: Config parsingEncoding detection+1

YAML Directives and Comments

A two-document stream where each document declares its own %YAML directive and the second adds a %TAG handle used by a local tag. Comments appear in every position they are legal, and every one of them is lost by a non-round-tripping loader.

File: YAML · YAML Edge Cases
Use case: Config parsingEncoding detection+1