Battle of the mocking frameworks
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From Sela Developer Practice 2013 In the real world, applications are so complex, that in order to test a component in isolation, you need a new set of tools. Without using a mocking framework it is impossible to write easy to read and maintain unit tests. The problem is that there are a lot of different frameworks to choose from – each has its merits and shortcomings. How can you choose the correct framework? What is the difference between the free alternatives to the costly commercial options and why should you care about error message… By the end of this talk you'll understand why you need a mocking framework and which framework is the best for your project.
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Battle of the mocking frameworks
- 1. SELA DEVELOPER PRACTICE May 5-9, 2013 Dror Helper Battle of the mocking frameworks
- 2. About.Me • Developing software (professionally) since 2002 • Disclaimer: I used to work at Typemock • Blogger: http://blog.drorhelper.com
- 3. This is a unit test [Test] public void AddTest() { var cut = new Calculator(); var result = cut.Add(2, 3); Assert.AreEqual(5, result); } This is not a real unit test
- 4. The problem - dependencies Unit test Code under test Dependency Dependency
- 5. The solution – Mocking! Unit test Code under test Dependency Fake object(s)
- 6. What is a “Mock object”? “mock objects are simulated objects that mimic the behavior of real objects in controlled ways” [From Wikipedia] I prefer to call them “Fakes”
- 7. What does a mocking framework do? 1. Create fake objects 2. Set behavior on fake objects 3. Verify method was called (Mock) 4. Much more
- 8. .NET Mocking frameworks Isolation Frameworks Open Source Commercial Isolator JustMock RhinoMocks Moq nSubtitute FakeItEasy NMock3 Free MS Fakes
- 9. Usage statistics Moq 45% Rhino Mocks 23% None 9% FakeItEasy 6% Nsubstitute 6% Isolator 4% Moles 2% MS Fakes 2% JustMocks 2% Other 1% any.html-if-use-you-do-framework-isolation-which-poll-/annual4/5/2012http://osherove.com/blog/
- 10. Choosing the right framework is important 1. Married into your code 2. Saves/waste time 3. Affects design
- 11. Round 1 - API
- 13. Round 2 - Robustness • What happens when: • Code under test API changed • Code under test internal change Future proof
- 15. Unconstraint vs. Constraint Isolation Frameworks Constraint Unconstraint Isolator JustMock RhinoMocks Moq nSubtitute FakeItEasy NMock3 MS Fakes
- 16. Constrained • Fake by inheritance • Force architecture • Dependency injection (DI) • Code by interfaces (LSP) • Boxing of the unfakeable Real object Fake object
- 17. Unconstrained • Profiler API based • Can fake almost anything • 3rd party systems • Legacy code • Design your code not for testability • Can be used as if they are constrained Real Object Dependency Fake
- 18. Nickels and dimes Constraint frameworks are free – can you afford them? How much does it cost if every task takes 1 hour more? How much does it cost not to use unit tests?
- 19. Round 4 - deployment Constraint
- 20. Deployment – the bottom line MS FakesJustMockIsolatorUnconstraint Only on VS11Install on each machine. Install on each machine. Auto-run correct version Nothing (NuGet) Dev machine Only on TFS2012Install on each machine. Install or use AutoDeploy NothingBuild Machine Only TFS2012Environment vars JustMockRunner Build Tasks Environment vars TMockRunner Build Tasks Just run itCI Only VS11 profilers Limited linker (nCover, dotTrace) Use Linker VS11 profilers Works!Profilers Support
- 21. Summery – what to choose?
- 22. Thank You
Editor's Notes
- Possible changes:CUT adds/remove a parameterDependency API changeAdd call to the same dependency without specifying in testChange to another overload of the same function