Exploratory Unit Testing

Python-sampling of unit testing ideas

Transcript

1. © 2026 CGI Inc. 1 Exploratory unit testing Maaret Pyhäjärvi February 2026
2. © 2026 CGI Inc. 2 Shift Down Test in smallest scale Test with developers Architecture-aware Granularity of feedback Speed of test execution AI -e nh an c ed a pp li c ati o n te s tin g
3. © 2026 CGI Inc. 3 Two styles of unit testing GUIDING PRINCIPLES
4. © 2026 CGI Inc. 4 Not magic, but magic tricks GUIDING PRINCIPLES Intentional shift down with Test doubles: stubs, mocks, fakes, spys
5. © 2026 CGI Inc. 5 The spec ROMAN NUMERALS
6. © 2026 CGI Inc. 6 How Would You Test This? Roman Numerals https://github.com/QE-at-CGI-FI/py-roman/
7. © 2026 CGI Inc. 7 Simplified architecture ROMAN NUMERALS UI (tkinter) Logic (to_roman function) Examples today in python
8. © 2026 CGI Inc. 8 Asserts for positive UNIT TESTING IN PYTHON
9. © 2026 CGI Inc. 9 Coverage UNIT TESTS IN PYTHON 90% covered coverage pytest-cov + coverage gutters -extension
10. © 2026 CGI Inc. 10 Asserts for negative – error handling logic UNIT TESTING IN PYTHON
11. © 2026 CGI Inc. 11 Approvals UNIT TESTING IN PYTHON
12. © 2026 CGI Inc. 12 Soft asserts; fail in the end and snapshots; autosave on 1st run UNIT TESTING IN PYTHON
13. © 2026 CGI Inc. 13 Properties with Hypothesis UNIT TESTING IN PYTHON
14. © 2026 CGI Inc. 14 Your imagination is the limit: inputs UNIT TESTING IN PYTHON
15. © 2026 CGI Inc. 15 Your imagination is the limit: boundaries UNIT TESTING IN PYTHON
16. © 2026 CGI Inc. 16 Your imagination is the limit: references UNIT TESTING IN PYTHON
17. © 2026 CGI Inc. 17 Your imagination is the limit: domains of use UNIT TESTING IN PYTHON
18. © 2026 CGI Inc. 18 Unit testing can be MORE GUIDING PRINCIPLES
19. © 2026 CGI Inc. 19 Testing not testers Skills and allocations of time drive choices Testability: allow testing also without dependencies Results score AI: 4 | AI with tester: 40 | Tester with AI: 73 | Testers: 13.5 AI -e nh an c ed a pp li c ati o n te s tin g Feb 2026 benchmark
20. © 2026 CGI Inc. 20 Insights you can act on Founded in 1976, CGI is among the largest IT and business consulting services firms in the world. We are insights-driven and outcomes-focused to help accelerate returns on your investments. Across hundreds of locations worldwide, we provide comprehensive, scalable and sustainable IT and business consulting services that are informed globally and delivered locally. cgi.com