From unit tests to continuous integration for Excel files. Write your Excel tests in Python. See also: https://www.youtube.com/watch?v=CHaNnYhb9Sw and https://github.com/xlwings/excel-automated-testing

1. Automated Testing of
Excel Workbooks
Felix Zumstein, 18 June 2019
xlwings Meetup London
From unit tests to continuous integration

2. Agenda
2
1. Introduction
2. Meetup organisation
3. xlwings intro
4. Talk: Automated Testing
5. Pub

3. 1. Introduction

4. Innovative Solutions
for Microsoft Excel
A small team with a big mission
4

5. Our Solutions (1/2)
Python for Excel
>>> import xlwings as xw
>>> xw.Book()
<Book [Book1]>
5
Version Control for Excel

6. Our Solutions (2/2)
6
git-xltrail
CI
(pilot)
Git extension for VBA
Continuous Integration
for Microsoft Excel

7. 2. Meetup Organisation

8. Meetup Organisation
8
• Community event
• About any innovative solution for Excel,
not just those based on xlwings
• Contact me if you want to give a talk
(short or long) in one of the next
meetups

9. 3. xlwings Intro

10. xlwings
10
1) Automation
2)Macros
3)UDFs (Windows only)
4)REST API
Except for UDFs, everything works on Mac
and Windows and requires an installation
of Excel.

11. 4. Automated Testing

12. What is a unit test (Python sample)?
12
Python function
that we want to test
Unit test:
OK or FAIL

13. Map VBA functions to Python
13
VBA function
Calling the
VBA
function
from Python

14. VBA unit test boilerplate
14
run at the
beginning
and end of
the test
suite,
respectively
actual test

15. What can be tested in Excel?
15
1) Unit test: E.g. a cell formula, a VBA function
or an xlwings UDF
2) Integration test: E.g. running an entire
macro or testing the effect of a cell change
on the whole workbook
3) Cell logic test: Test dynamic tables
4)Alternative implementation test: E.g.
comparing a VBA function with a function
available in (a tested) 3rd party library

16. 1a) VBA unit test
16

17. 1a) Cell formula unit test
17

18. 2) VBA integration test
18

19. 3) Cell logic test
19

20. 4) Alternative Implementation Test
20

21. Run the tests
21
To run a single test:
python -m unittest test_mybook.TestMyBook.test_vba_unittest

22. Unittest runners/frameworks
22
1) unittest: built-in
2) pytest
3) nose/nose2

23. Continuous Integration (1/2)
23
1) Use Git for version control
2) The tests are automatically run on a server
whenever you push a new version

24. Continuous Integration (2/2)
24

25. Thank You