Implementing TDD in for .net Core applications

Implementing TDD in for .net Core applications

• 1.
  TDD Test Driven Development
• 2.
  What is TDD?  Test Driven Development (First test programming)  Is a software development process  It’s actually an approach to design and develop testable code  It’s base on short 5 step cycles  1-Start with writing unit tests. Unit tests are written based on Specs and Failure conditions (e.g. boundary conditions, potential exceptions, ...)  2-Run the unit tests and confirm that they fail  3-Then implement the actual methods to pass the tests  4-Run tests and confirm they pass  5-Refactor your code (Clean up the code, remove duplications …)
• 3.
  Why TDD?  Automatedtesting (saves a lot of time for assuring code’s health)  Facilitates debugging (saves a lot of time in detecting problems)  Protects the code from breaking changes  Facilitates Continuous Integration (CI) and Delivery  Improves the app design and quality of the code  Forces developers to comply with SOLID design principles  Single Responsibility, Open-Closed, Liskov substitution, Interface Segregation, Dependency inversion
• 4.
  Types of Tests Unit test  A unit test is actually a class that tests another app component (another class)  A unit test method Only tests a single unit of work (a method)  There should be no dependency to Database, File, Network or any other I/O resources whatsoever. Everything should happen in the memory  So they should pass all the time, otherwise something’s wrong with code  Integration test  It’s a class that tests combination of multiple units of work  It’s OK to have dependencies to I/O resources  So Configuration of dependencies (e.g. connection string) could result in test failure  Functional Test (a.k.a E2E test)  Manual tests (QA’s Job)  Automated E2E tests
• 5.
  Unit Testing  Unittest classes  Unit Test Methods  3 main sections :  Arrange  Initialize values, fake dependencies  Act  Run the System under test (SUT), actually the Method under test  Assert  Check the return value or system status against expected values/criteria
• 6.
  Example Arrange Act Assert
• 7.
  Unit Test Tools Tools for Running Tests and Asserting results  Unit Test Frameworks :  Back-end (C#.net): MS Test, xUnit.net, NUnit, MbUnit, etc.  Front-end (JS/AngularJS2): Jasmine, Chai, QUnit , etc.  Tools for faking dependencies  Isolation Frameworks :  Back-end (C#.net): Moq, NSubstitute, MS Fakes (Moles), JustMock, TypeMock, Rhino Mocks  Front-end (JS): Jasmine, SinonJs
• 8.
  Back-end Unit TestingFrameworks Feature MS Test (v2) XUnit.net (v2.x) NUnit (v3) MbUnit DNX/.net Core Support YES YES YES but in next version’s RC NO Community No Open Source community 50 Contributors 3 Active Devs 1144 Stars Part of .NET Foundation 74 Contributors 8 Active Devs 763 Stars Weak Latest update Oct 2014 VS Integration YES YES (Through plug-ins) YES (Through plug-ins) YES (Through plug-ins) Supported by CI Tools TFS, VS Online, Team City, Jenkins TeamCity, Jenkins, VS Online, TFS TeamCity, Jenkins, VS Online, TFS TFS Parallel Execution Support YES (Per Test Class) – newly added YES (Per Test Method) Yes (Per Test Class) NO Extensible (Through Attribute Inheritance) NO YES YES but limited and not documented yet NO Parameterized Test YES YES YES YES Performance Supposed to be slower Faster (due to parallelism) Fast No comments found Other • Not as active as the others and Slower in releasing new versions • The most modern, Part of .NET Foundation • More TDD adherence • 1 instance per test method • Resharper integration • Prevents bad habits • .NET Core’s Default • Widely used, currently de facto FW, Posted from Java • Parameterized tests • 1 instance for all test methods • Resharper integration • Well Documented Seems to be dying! The most popular frameworks in .NET landscape :
• 9.
  Types of IsolationFrameworks  Constrained  Constrained to .net Compiler restrictions as they generate .net code and compile it at runtime  Can only mock public, non static members, no sealed classes  Unconstrained  They use unmanaged APIs (Profiling APIs). They wrapped around the running instance of CLR and are able to manipulate the way that managed code works  They can fake almost everything, private members, static members, and even 3rd party stuff
• 10.
  Back-end Isolation Frameworks Moq(4.x) NSubstitute MSFakes (Moles) TypeMock FakeItEasy Framework Type Constrained Constrained Unconstrained Unconstrained (Commercial) Constrained (Free) Constrained Needs profiling to be enabled NO NO YES YES (Commercial) No (Free) NO Can fake 3rd Party systems NO NO YES YES(Commercial) No (Free) NO .net Core Support YES YES YES Not Yet NO Community 44 Contributors 6 Active Contributors 1460 Stars 31 Contributors 5 Active Contributors 696 Stars Not Open source Not Open source 24 Contributor 6 Active Contributors 595 Notes • The most popular one • More Readable • Less readability Only for 3rd Party Components99% of cases
• 11.
  Conclusion  Test runner/Frameworkfor .net : XUnit.net  .net Core Support, well adopted by community and being a part of .NET Foundation  Forces testing best practices (through 1 instance per method approach)  Good performance  NUnit could be an option if we care about the abundance of resources (Stackoverflow, blog articles, …) but XUnit.net is future proof  Isolation Framework for .net : Moq (for 99% of cases), MSFakes (just for mocking non-mockable 3rd party components)  Moq is widely used, well documented and mature enough.  MSFakes is the only free unconstrained FW among major players  Use FluentAssertions for better test readability
• 12.
  Final Points  Fora real production code unit testing is a must, not just a choice  What matters more than tools and frameworks we’re using, is writing a well- designed testable code and being committed to testing.  Watching Code Coverage and keeping it high  Code and Test Review to prevent cutting corners and maintain the test and code quality  In the front-end we need to do unit testing as well. As it’s got UI logic in it and exactly because of design and clean code concerns De facto libs for testing AngularJS apps are : Jasmine (Unit test FW) ,Karma (Test Runner), Protractor (code driven End-to-End automated test for AngularJS 2) runs on top of Selenium Webdriver