CSV Desk tutorial test notes
Test date: October 6, 2026 (Asia/Shanghai)
Application: Microsoft Excel for Mac 16.113.2 (26092012), Microsoft 365
Interface language: Chinese. Formulas and fictional test data: English.

Method
Two separate worksheets in a new local workbook were used. Input ranges were
formatted as Text before literal values were written through the connected
Excel session. Formula patterns were entered, filled down and read back with
their calculated values. These were native Excel calculations, not cached
answers generated by a CSV parser. The test did not exercise a new CSV import
dialog, Windows Excel, Power Query or an English-language Excel interface.

Date test
Input: dates-validation-input.csv, 12 data records, 3 fields per record.
Expected contract: DMY dd/mm/yyyy, MDY mm/dd/yyyy, ISO yyyy-mm-dd;
years 1901-9999; missing and unknown-format values retained with statuses.
All 12 output/status pairs matched dates-validation-expected.csv.
Accepted: D01, D02, D03, D07 (4 rows).
Invalid: D05, D08, D09, D10, D11, D12 (6 rows).
Review: D04. Missing: D06.
Observed negative control: DATE rolled 31/02/2026 into 2026-03-03;
the round-trip text check rejected it and withheld the final output.
Recalculation: changing D08's input from 29/02/2025 to 28/02/2025 changed
the result from invalid/blank to accepted/2025-02-28. Restoring the input
returned invalid/blank. Final worksheet outputs were read again.

Two-list comparison
Inputs: compare-left.csv and compare-right.csv; 8 data records each.
Rule: case-sensitive literal equality, preserving leading zeros;
blank keys are withheld, not matched to other blank keys.
All 8 left-side results matched compare-expected.csv:
2 one match, 4 not found, 1 duplicate in reference, 1 missing key.
All 8 reverse results matched compare-reverse-expected.csv:
4 one match, 3 not found, 1 missing key.
Observed cases: 0127 did not match 00127 or 127; AbC-7 did not match abc-7;
A*1 did not match AB1; DUP matched two reference rows.
Recalculation: changing reference abc-7 to AbC-7 changed L04 to one match.
Restoring abc-7 returned L04 to not found. Final outputs were read again.

Independent checks
CSV parsing, exact record counts, field counts, SHA-256 file hashes,
calendar-date validation, case-sensitive string counts, and expected outputs
are checked separately from Excel. The practice ZIP contains a manifest.

Limits
These finite cases do not certify every dataset, locale or Excel version.
The workbook was controlled through the connected Excel tools; this is not
a claim of a human reader independently following every article step.
Neither a matching ID nor a matching row count proves complete-record equality.
All sample records are fictional. Keep an unchanged copy of real input files.