feat(xlsx): create a page for each worksheet in XLSX backend (#1332)

* sytle(xlsx): enforce type hints in XLSX backend

Signed-off-by: Cesar Berrospi Ramis <75900930+ceberam@users.noreply.github.com>

* feat(xlsx): create a page for each worksheet in XLSX backend

Signed-off-by: Cesar Berrospi Ramis <75900930+ceberam@users.noreply.github.com>

* docs(xlsx): add docstrings to XLSX backend module.

Signed-off-by: Cesar Berrospi Ramis <75900930+ceberam@users.noreply.github.com>

* docling(xlsx): add bounding boxes and page size information in cell units

Signed-off-by: Cesar Berrospi Ramis <75900930+ceberam@users.noreply.github.com>

---------

Signed-off-by: Cesar Berrospi Ramis <75900930+ceberam@users.noreply.github.com>

tests/test_backend_msexcel.py

@@ -1,13 +1,18 @@
-import os
+import logging
 from pathlib import Path
 
+import pytest
+
+from docling.backend.msexcel_backend import MsExcelDocumentBackend
 from docling.datamodel.base_models import InputFormat
-from docling.datamodel.document import ConversionResult, DoclingDocument
+from docling.datamodel.document import ConversionResult, DoclingDocument, InputDocument
 from docling.document_converter import DocumentConverter
 
 from .test_data_gen_flag import GEN_TEST_DATA
 from .verify_utils import verify_document, verify_export
 
+_log = logging.getLogger(__name__)
+
 GENERATE = GEN_TEST_DATA
 
 
@@ -28,13 +33,15 @@ def get_converter():
     return converter
 
 
-def test_e2e_xlsx_conversions():
+@pytest.fixture(scope="module")
+def documents() -> list[tuple[Path, DoclingDocument]]:
+    documents: list[dict[Path, DoclingDocument]] = []
 
     xlsx_paths = get_xlsx_paths()
     converter = get_converter()
 
     for xlsx_path in xlsx_paths:
-        print(f"converting {xlsx_path}")
+        _log.debug(f"converting {xlsx_path}")
 
         gt_path = (
             xlsx_path.parent.parent / "groundtruth" / "docling_v2" / xlsx_path.name
@@ -44,6 +51,14 @@ def test_e2e_xlsx_conversions():
 
         doc: DoclingDocument = conv_result.document
 
+        assert doc, f"Failed to convert document from file {gt_path}"
+        documents.append((gt_path, doc))
+
+    return documents
+
+
+def test_e2e_xlsx_conversions(documents) -> None:
+    for gt_path, doc in documents:
         pred_md: str = doc.export_to_markdown()
         assert verify_export(pred_md, str(gt_path) + ".md"), "export to md"
 
@@ -57,3 +72,30 @@ def test_e2e_xlsx_conversions():
         assert verify_document(
             doc, str(gt_path) + ".json", GENERATE
         ), "document document"
+
+
+def test_pages(documents) -> None:
+    """Test the page count and page size of converted documents.
+
+    Args:
+        documents: The paths and converted documents.
+    """
+    # number of pages from the backend method
+    path = [item for item in get_xlsx_paths() if item.stem == "test-01"][0]
+    in_doc = InputDocument(
+        path_or_stream=path,
+        format=InputFormat.XLSX,
+        filename=path.stem,
+        backend=MsExcelDocumentBackend,
+    )
+    backend = MsExcelDocumentBackend(in_doc=in_doc, path_or_stream=path)
+    assert backend.page_count() == 3
+
+    # number of pages from the converted document
+    doc = [item for path, item in documents if path.stem == "test-01"][0]
+    assert len(doc.pages) == 3
+
+    # page sizes as number of cells
+    assert doc.pages.get(1).size.as_tuple() == (3.0, 7.0)
+    assert doc.pages.get(2).size.as_tuple() == (9.0, 18.0)
+    assert doc.pages.get(3).size.as_tuple() == (13.0, 36.0)