test(extract): hand-built office fixtures with frozen extracted text

Three hand-laid OOXML containers, every part written out by hand and zipped
with a fixed date_time so they are byte-reproducible. No converter output
anywhere in them: a .docx written by the converter and read by the converter
proves only that the converter agrees with itself, and would stay green through
any conversion defect that is symmetric -- which is most of them.

  two-line-krav.docx    heading + label/value on one line (the docx mirror of
                        the PDF fixture)
  no-styles-krav.docx   the SAME document without word/styles.xml
  two-line-krav.xlsx    sheet name as heading + label/value on one row

THE FIXTURES FOUND A REAL DEFECT IN THE SEAM THEY WERE MEANT TO PIN. The
converter call used pypandoc's TEXT entry point, which takes an `encoding`
because it treats its source as text -- and that corrupts a zip. The xlsx
fixture failed with `Failed to unpack XLSX archive: not enough bytes` while
reading correctly from disk with the same binary. The docx of the same shape
happened to survive, which is the part worth writing down: the defect is silent
for some inputs and fatal for others, so "it worked on the file I tried" was
never evidence. Input now goes through a temporary file.

Two measurements while building, both the same shape -- structurally valid
input, silently reduced output, exit code 0, no warning:

- Without word/styles.xml the docx extracts as flat prose with no heading. A
  fixture lacking that part would pin the body and pin nothing about structure.
  Committed as a negative control that RUNS rather than a sentence in a README.
- With inline strings rather than a shared string table, the xlsx extracts with
  the sheet name intact and every cell value gone. The fixture uses a dimension
  element and a shared string table instead.

The frozen literals are pinned to a NAMED converter version, asserted beside
them: a frozen literal without one says "these bytes" without saying what
produced them.

Suite 908 -> 913. Fixtures regenerate byte-identically.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/fixtures/README.md

@@ -18,6 +18,43 @@ and reproducible from that one file.
 | `two-line-krav.pdf` | One heading plus one requirement row with label and value on the **same line**. That pairing is the property `pdfplumber` was chosen for. |
 | `no-text-layer.pdf` | A structurally valid page with no text operators — the shape a scanned or image-only PDF presents. Must fail fast (`extractor_empty_pdf`), never persist as an empty concept. |
 
+## The office fixtures
+
+`two-line-krav.docx`, `no-styles-krav.docx` and `two-line-krav.xlsx` are
+hand-laid OOXML containers, regenerated by the same `make_fixtures.py`. Every
+part is written out by hand and zipped with a fixed `date_time`, so they are
+byte-reproducible and carry no converter's output.
+
+**That last point is the whole policy, not a preference.** A `.docx` written by
+the converter and then read by the converter proves only that the converter
+agrees with itself, and would stay green through any conversion defect that is
+symmetric — which is most of them.
+
+| Fixture | What it is for |
+|---|---|
+| `two-line-krav.docx` | A heading plus one requirement row with label and value on the **same line** — the docx mirror of `two-line-krav.pdf`. |
+| `no-styles-krav.docx` | The **same document without `word/styles.xml`**. A negative control: the body survives and the heading marker does not, which is what proves the styles part is load-bearing rather than decoration. |
+| `two-line-krav.xlsx` | A sheet name that becomes a heading, plus a label/value pair on one row. |
+
+Two things were measured while building these, and both are the same shape —
+structurally valid input, silently reduced output, exit code 0 and no warning:
+
+- **Without `word/styles.xml`** the docx extracts as flat prose with no heading.
+  A fixture lacking that part would pin the body and pin nothing about
+  structure, while looking exactly as convincing. Structure is the half the
+  segment proposer reads.
+- **With inline strings (`t="inlineStr"`)** rather than a shared string table,
+  the xlsx extracts with the sheet name intact and **every cell value gone**.
+  The fixture therefore uses a `dimension` element and a shared string table.
+
+## Why the expected office text is frozen as a literal
+
+The same reason as the PDF text below, with one addition: the literals are
+pinned to a **named converter version**. `_pandoc.py` refuses any binary but
+the vendored 3.9, and `tests/test_extract.py` asserts that version beside the
+literals. A frozen literal without a named converter pins nothing — it says
+"these bytes" without saying what produced them.
+
 ## Why the expected PDF text is frozen as a literal
 
 `tests/test_extract.py` asserts the extracted text of `two-line-krav.pdf` as an

tests/fixtures/make_fixtures.py

@@ -1,14 +1,23 @@
-"""Regenerate the committed PDF fixtures for tests/test_extract.py.
+"""Regenerate the committed fixtures for tests/test_extract.py.
 
-Hand-written minimal PDFs: objects laid out by hand, xref offsets computed
-from the emitted bytes. No generator library, so the fixtures are auditable
-byte for byte and reproducible from this file alone.
+Hand-written minimal documents: PDF objects laid out by hand with xref offsets
+computed from the emitted bytes, and OOXML containers assembled part by part.
+No generator library anywhere, so every fixture is auditable byte for byte and
+reproducible from this file alone.
+
+THE POLICY IS WHAT FORBIDS THE SHORTCUT. A `.docx` written by the converter and
+then read by the converter proves only that the converter agrees with itself --
+it would stay green through any conversion defect that is symmetric, which is
+most of them. Hand-laying the parts is what makes the fixture an independent
+statement about the format rather than a recording of our own output.
 
 Run from the repository root:  python3 tests/fixtures/make_fixtures.py
 """
 
 from __future__ import annotations
 
+import io
+import zipfile
 from pathlib import Path
 
 HERE = Path(__file__).parent
@@ -55,6 +64,121 @@ def build_pdf(content: bytes) -> bytes:
     return bytes(out)
 
 
+# --- office containers -------------------------------------------------------
+#
+# A fixed timestamp on every member, because a zip records mtime and the whole
+# point is a byte-reproducible file: without it the fixture would differ on
+# every regeneration and `git diff --quiet` could never be the check.
+_ZIP_DATE = (2020, 1, 1, 0, 0, 0)
+
+_XML = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>'
+
+# `word/styles.xml` IS REQUIRED, not decoration. Measured during planning: the
+# same document WITHOUT a styles part extracts as plain text with no heading
+# marker at all, so a fixture lacking it would pin the body and silently pin
+# nothing about structure -- which is the half the segment proposer reads.
+_DOCX_PARTS = {
+    "[Content_Types].xml": _XML
+    + '<Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types">'
+    + '<Default Extension="xml" ContentType="application/xml"/>'
+    + '<Default Extension="rels" ContentType="application/vnd.openxmlformats-package.relationships+xml"/>'
+    + '<Override PartName="/word/document.xml" ContentType="application/vnd.openxmlformats-officedocument.wordprocessingml.document.main+xml"/>'
+    + '<Override PartName="/word/styles.xml" ContentType="application/vnd.openxmlformats-officedocument.wordprocessingml.styles+xml"/>'
+    + "</Types>",
+    "_rels/.rels": _XML
+    + '<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">'
+    + '<Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument" Target="word/document.xml"/>'
+    + "</Relationships>",
+    "word/_rels/document.xml.rels": _XML
+    + '<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">'
+    + '<Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/styles" Target="styles.xml"/>'
+    + "</Relationships>",
+    "word/styles.xml": _XML
+    + '<w:styles xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main">'
+    + '<w:style w:type="paragraph" w:styleId="Heading1"><w:name w:val="heading 1"/></w:style>'
+    + "</w:styles>",
+    "word/document.xml": _XML
+    + '<w:document xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main"><w:body>'
+    + '<w:p><w:pPr><w:pStyle w:val="Heading1"/></w:pPr><w:r><w:t>Krav til helning</w:t></w:r></w:p>'
+    + "<w:p><w:r><w:t>60 og 70 1:15</w:t></w:r></w:p>"
+    + "</w:body></w:document>",
+}
+
+# The same document MINUS the styles part. A negative control, committed rather
+# than described: it is what proves the styles part is load-bearing, and a
+# claim of that kind that nothing runs is a claim that decays.
+_DOCX_NO_STYLES_PARTS = {
+    "[Content_Types].xml": _XML
+    + '<Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types">'
+    + '<Default Extension="xml" ContentType="application/xml"/>'
+    + '<Default Extension="rels" ContentType="application/vnd.openxmlformats-package.relationships+xml"/>'
+    + '<Override PartName="/word/document.xml" ContentType="application/vnd.openxmlformats-officedocument.wordprocessingml.document.main+xml"/>'
+    + "</Types>",
+    "_rels/.rels": _DOCX_PARTS["_rels/.rels"],
+    "word/document.xml": _DOCX_PARTS["word/document.xml"],
+}
+
+# A minimal SpreadsheetML workbook: one sheet, a heading row and a label/value
+# row, mirroring what the PDF fixture does for its format.
+#
+# THE SHARED STRING TABLE IS NOT A STYLE CHOICE. The first attempt used inline
+# strings (`t="inlineStr"`), which is valid SpreadsheetML and which the
+# converter reads as EMPTY CELLS -- the sheet name survived and every value
+# vanished, with exit code 0 and no warning. A `dimension` element and a shared
+# string table are what make the values arrive. This is the same class of
+# defect as the missing `styles.xml`: structurally valid input, silently
+# reduced output, nothing anywhere saying so.
+_XLSX_PARTS = {
+    "[Content_Types].xml": _XML
+    + '<Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types">'
+    + '<Default Extension="xml" ContentType="application/xml"/>'
+    + '<Default Extension="rels" ContentType="application/vnd.openxmlformats-package.relationships+xml"/>'
+    + '<Override PartName="/xl/workbook.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.main+xml"/>'
+    + '<Override PartName="/xl/worksheets/sheet1.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.worksheet+xml"/>'
+    + '<Override PartName="/xl/sharedStrings.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.sharedStrings+xml"/>'
+    + "</Types>",
+    "_rels/.rels": _XML
+    + '<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">'
+    + '<Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument" Target="xl/workbook.xml"/>'
+    + "</Relationships>",
+    "xl/_rels/workbook.xml.rels": _XML
+    + '<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">'
+    + '<Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/worksheet" Target="worksheets/sheet1.xml"/>'
+    + '<Relationship Id="rId2" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/sharedStrings" Target="sharedStrings.xml"/>'
+    + "</Relationships>",
+    "xl/workbook.xml": _XML
+    + '<workbook xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main"'
+    + ' xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships">'
+    + '<sheets><sheet name="Krav" sheetId="1" r:id="rId1"/></sheets></workbook>',
+    "xl/sharedStrings.xml": _XML
+    + '<sst xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" count="3" uniqueCount="3">'
+    + "<si><t>Krav til helning</t></si><si><t>60 og 70</t></si><si><t>1:15</t></si></sst>",
+    "xl/worksheets/sheet1.xml": _XML
+    + '<worksheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main">'
+    + '<dimension ref="A1:B2"/><sheetData>'
+    + '<row r="1"><c r="A1" t="s"><v>0</v></c></row>'
+    + '<row r="2"><c r="A2" t="s"><v>1</v></c><c r="B2" t="s"><v>2</v></c></row>'
+    + "</sheetData></worksheet>",
+}
+
+
+def build_ooxml(parts: dict[str, str]) -> bytes:
+    """Zip the parts with a fixed timestamp and no compression variance.
+
+    A constant `date_time` on every member is what makes the output
+    reproducible: a zip records mtime, so the default `ZipFile.writestr` would
+    stamp the current time and the fixture would differ on every run --
+    which would make `git diff --quiet` useless as the regeneration check.
+    """
+    out = io.BytesIO()
+    with zipfile.ZipFile(out, "w", compression=zipfile.ZIP_DEFLATED) as archive:
+        for name, payload in parts.items():
+            info = zipfile.ZipInfo(name, date_time=_ZIP_DATE)
+            info.compress_type = zipfile.ZIP_DEFLATED
+            archive.writestr(info, payload)
+    return out.getvalue()
+
+
 if __name__ == "__main__":
     for name, content in (
         ("two-line-krav.pdf", KRAV_CONTENT),
@@ -62,3 +186,11 @@ if __name__ == "__main__":
     ):
         (HERE / name).write_bytes(build_pdf(content))
         print(f"wrote {name}")
+
+    for name, parts in (
+        ("two-line-krav.docx", _DOCX_PARTS),
+        ("no-styles-krav.docx", _DOCX_NO_STYLES_PARTS),
+        ("two-line-krav.xlsx", _XLSX_PARTS),
+    ):
+        (HERE / name).write_bytes(build_ooxml(parts))
+        print(f"wrote {name}")