C++ Unit testing - the good, the bad & the ugly
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The document discusses C++ unit testing, highlighting the benefits of early bug detection and sustainable code management. It reviews various unit testing frameworks and mocking tools, noting their strengths, weaknesses, and the importance of keeping tools up-to-date. Ultimately, it encourages developers to adopt unit testing practices to avoid issues and improve software quality.
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What is a “Mock”?
“mock objects are simulated objects that
mimic the behavior of real objects in
controlled ways”
[From Wikipedia]
I prefer to call them “Fakes”](https://image.slidesharecdn.com/mujfkunr4yd4kzqb2weg-signature-0f167db20317343646b1d2d896846c4710d4a11b4cdeab7582cbe99228b82b99-poli-170615111110/85/C-Unit-testing-the-good-the-bad-the-ugly-15-320.jpg)
C++ Unit testing - the good, the bad & the ugly
- 1. C++ Unit testing The good, the bad and the ugly Dror Helper | @dhelper | http://helpercode.com
- 2. Consultant @CodeValue Developing software since 2002 Clean Coder & Test Driven Developer Pluralsight author https://www.pluralsight.com/authors/dror-helper B: http://helpercode.com T: @dhelper About.ME
- 3. An ode to C++ Multi-paradigm Performance & Speed Truly multi-platform Plays well with others Extendible and powerful Low level programming My compiler compiled your compiler’s compiler
- 4. “C makes it easy to shoot yourself in the foot; C++ makes it harder, but when you do it blows your whole leg off.” Bjarne Stroustrup
- 5. Avoid stupid bugs Early feedback Avoid Regression Write Sustainable, manageable code Route to modular OO design In code documentation Have you tried unit testing your code?
- 6. Definition: Unit Test (by me) A method (code) that tests specific functionality, Has clear pass/fail criteria and runs in isolation
- 7. This is a unit test (GTest) TEST(MovieTests, WhatWouldTucoDo) { Charcter tuco; tuco.SetHaveToShoot(true); ASSERT_FALSE(tuco.GetTalk()); }
- 8. What you’ll need Developer’s Machine • Unit testing framework • Mocking framework • Code coverage tool • Other (IDE, Refactoring tools) Continuous Integration • CI Server • Build Agent(s)
- 9. Unit testing framework capabilities Tests & Fixtures Assertio ns Test Runners
- 10. C++ Unit Testing Frameworks The Good • Many choices • Many Styles The Bad • Documentation may vary • Not all maintained The Ugly • Deployment • No Reflection…
- 11. * at least until C++/2020
- 12. C++ Unit Testing Frameworks GTest MSTest Catch CppUnit Boost.Test DocTest lest xUnit++ Mettle A Short, incomplete list…
- 13. Multiple asserts • Lose information • Complex tests One assert per test • Writing many tests for the same scenario • See Above The multiple assertion dilemma
- 14. Innovation in C++ Enabling readable and maintainable tests • Failures without exceptions • Better failure messages • Single, powerful assert • Rethinking test fixture - Sections
- 15. 16 What is a “Mock”? “mock objects are simulated objects that mimic the behavior of real objects in controlled ways” [From Wikipedia] I prefer to call them “Fakes”
- 16. Mocking frameworks responsibilities 1. Create Fake/Mock objects 2. Set behavior on fakes 3. Verify that methods were called
- 17. C++ Mocking Frameworks The Good • C++ has mocking frameworks The Bad • I meant a framework (at least until recently) • Beware of dead projects The Ugly • Most one step better than hand rolled mocks • Most are not AAA compliant
- 18. C++ Mocking Frameworks GMock Trompeloeil HippoMocks FakeIt *Based on my own experience
- 19. Don’t use obsolete tools! 1. Check when was the last commit! 2. How extensive is the documentation C++ is changing and so should your testing framework
- 20. C++ Development in Windows • Multi-platform – develop on windows, compile to run everywhere • Remote debug/run on Linux (VS2017) • Use test runner (or develop your own) • Code coverage support
- 21. How to choose your unit testing tools Multi-platform vs. mono-platform Ease of use What happens when test fails Integration points Runner Support Ease of deployment Personal taste
- 22. IN THIS WORLD THERE’S TWO TYPES OF PEOPLE MY FRIEND. THOSE WITH UNIT TESTS AND THOSE WHO BLAME. WRITE UNIT TESTS!
- 23. Thank you Dror Helper | @dhelper | http://helpercode.com
Editor's Notes
- #8: A method (code) that tests specific functionality, Has clear pass/fail criteria and runs in isolation