feat: add Excel export functionality with support for metadata and customizable sheets

tests/test_export_serializers.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 from dataclasses import dataclass
 from datetime import date, datetime, timezone
 from decimal import Decimal
+from io import BytesIO
 from typing import Any, Iterable
 
 import pytest
@@ -10,15 +11,19 @@ import pytest
 from services.export_serializers import (
     CSVExportColumn,
     CSVExporter,
+    ExcelExporter,
     default_formatter,
     default_project_columns,
     default_scenario_columns,
+    export_projects_to_excel,
+    export_scenarios_to_excel,
     format_date_iso,
     format_datetime_utc,
     format_decimal,
     stream_projects_to_csv,
     stream_scenarios_to_csv,
 )
+from openpyxl import load_workbook
 
 
 @dataclass(slots=True)
@@ -50,6 +55,11 @@ def collect_csv_bytes(chunks: Iterable[bytes]) -> list[str]:
     return [chunk.decode("utf-8") for chunk in chunks]
 
 
+def load_workbook_bytes(data: bytes):
+    buffer = BytesIO(data)
+    return load_workbook(buffer, read_only=True, data_only=True)
+
+
 def test_csv_exporter_writes_header_and_rows() -> None:
     exporter = CSVExporter(
         [
@@ -66,6 +76,64 @@ def test_csv_exporter_writes_header_and_rows() -> None:
     assert chunks[1] == "Alpha,Nevada\n"
 
 
+def test_excel_exporter_basic_workbook() -> None:
+    exporter = ExcelExporter(default_project_columns(), sheet_name="Projects")
+    project = DummyProject(name="Alpha", location="Nevada")
+
+    data = exporter.export([project])
+    workbook = load_workbook_bytes(data)
+    sheet = workbook["Projects"]
+    rows = list(sheet.rows)
+
+    assert [cell.value for cell in rows[0]] == [
+        "name",
+        "location",
+        "operation_type",
+        "description",
+        "created_at",
+        "updated_at",
+    ]
+    assert rows[1][0].value == "Alpha"
+
+
+def test_excel_export_projects_helper_with_metadata() -> None:
+    project = DummyProject(name="Alpha", location="Nevada")
+    data = export_projects_to_excel(
+        [project], metadata={"rows": 1}, workbook_title="Project Export")
+
+    workbook = load_workbook_bytes(data)
+    assert workbook.properties.title == "Project Export"
+    assert "Projects" in workbook.sheetnames
+    assert any(sheet.title.startswith("Metadata")
+               for sheet in workbook.worksheets)
+
+
+def test_excel_export_scenarios_helper_projects_resolved() -> None:
+    project = DummyProject(name="Alpha")
+    scenario = DummyScenario(project=project, name="Scenario 1")
+    data = export_scenarios_to_excel([scenario])
+
+    workbook = load_workbook_bytes(data)
+    sheet = workbook["Scenarios"]
+    rows = list(sheet.rows)
+
+    assert rows[1][0].value == "Alpha"
+    assert rows[1][1].value == "Scenario 1"
+    exporter = CSVExporter(
+        [
+            CSVExportColumn("Name", "name"),
+            CSVExportColumn("Location", "location"),
+        ]
+    )
+
+    project = DummyProject(name="Alpha", location="Nevada")
+
+    chunks = collect_csv_bytes(exporter.iter_bytes([project]))
+
+    assert chunks[0] == "Name,Location\n"
+    assert chunks[1] == "Alpha,Nevada\n"
+
+
 def test_csv_exporter_handles_optional_values_and_default_formatter() -> None:
     exporter = CSVExporter(
         [