Test driven development (TDD) in product development.pdf
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Test Driven Development (TDD) significantly reduces the number of bugs in software by preventing simple programming mistakes, leading to a decrease in defect density by 40% to 90%. However, TDD may not be suitable for all scenarios, such as GUI development, and can slow down initial development processes. While it promotes better quality and maintainability, it also requires careful implementation and maintenance of test code.
Test driven development (TDD) in product development.pdf
- 1. TDD in Product Development Beroza Paul Sr. software engineer
- 2. Truth about Software Product Development ● Industry average experience is about 1-25 bugs per 1000 lines of code for delivered software. ● 7-12 bugs per 1,000 lines of code find their way to the customers ● Fixing a bug takes 30 times longer than writing a line of code ● 75% of a developer’s time is spent on debugging (1500 hours a year!) Source: Code Complete by Steve McConnell
- 3. Production Bug is Expensive! ● Fixing a production bug may cost 100x more than fixing a bug at design time. ● Fixing a production bug may cost 15x more than fixing a bug at implementation time. Source: The Economics of Software Quality
- 4. Relative Costs of Fixing Bugs
- 5. How to reduce this cost?
- 6. Facts of Production Bug ● Most production bugs caused by simple programming mistakes ● 58% of them are trivial and can be addressed with test coverage ● Tiny mistakes will have huge impact on production
- 7. How to reduce trivial bugs?
- 8. Test Driven Development (TDD)?
- 10. TTD Reduces total cost? Source: The Economics of Software Quality
- 11. TTD Results in Fewer Bugs? ● A case study of engineering teams at Microsoft and IBM showed that the defect density decreased between 40% and 90% relative to similar projects that did not use the TDD practice. Source: Quality improvements
- 12. TDD Produces Better Quality? ● A study carried out among developers with 10+ years of professional experience (on average), to investigate their perceptions when employing TTD. Many of them agreed that “TDD allows greater quality and maintainability” Source: TDD analysis
- 13. TDD Promotes Simpler Design? ● The Department of Computer Science at North Carolina State University, ran an experiment with two groups of programmers: one used TDD and the other the linear approach. ● It turned out that “92% of developers believed that TDD yields higher quality code, 79% thought that TDD promotes simpler design. Source: TDD investigation
- 14. When TDD is wrong choice?
- 15. Developing GUI With TDD ● Trying to test the exact placement of UI components is pointless. First because layout is subjective and should be "tested" by humans
- 16. TDD experience in team ● An enthusiastic team and at least one experienced developer who knows how to write good tests and also knows a few things about good architecture, otherwise think twice before going down the TDD road.
- 17. TDD slows down initial process ● If you’re pressed for time and need to quickly launch your product or solution, the TDD approach may not be your best choice
- 18. Test Code Requires Maintenance ● All lines of code require maintenance, which means cost. The cost is easiest to acknowledge when a change to existing functionality is made.
- 19. TDD approach is difficult ● In TDD we need mocks/stubs etc. When we start using mocks, after a while, we will want to start using Dependency Injection (DI) and a Inversion of Control (IoC) container. To do that you need to use interfaces for everything. At the end we end up writing lot more code.
- 20. Thank you!