2. AGENDA
What is TDD?
The Benefits and Limitations of TDD
Common Pitfalls of TDD
REST-API TDD with Node.js
Demo
Question?
3. WHAT IS TDD?
TDD: Test Driven Development refers to a style of programming
in which three activities are tightly interwoven
1. Coding
2. Testing (Unit Test)
3. Design (Refactoring)
Basic Philosophy
1. write a "single" unit test describing an aspect of the program
2. run the test, which should fail because the program lacks that feature
3. write "just enough" code, the simplest possible, to make the test pass
4. "refactor" the code until it conforms to the simplicity criteria
5. repeat, "accumulating" unit tests over time
5. THE BENEFITS AND LIMITATIONS
Benefits
1. Writing tests first require you to really consider what you want from the code
2. Short feedback loop
3. Reduced time in rework
4. Less time spent in the debugger
5. Simplification & Loose Coupling (DI)
6. Improves quality and reduces bugs
Limitations
1. Bigger up-front cost
2. Some codes are difficult to write the test.
3. Focus on micro-design not macro-design
4. Need to use mock to reproduce the real world.
5. Cannot cover all functional testing (UI, DB, Network,…)
6. COMMON PITFALLS
Individual mistakes
1. Forgetting to run tests frequently
2. Writing too many tests at once
3. Writing tests that are too large or coarse-grained
4. Writing overly trivial tests, for instance omitting assertions
5. Writing tests for trivial code, for instance assessors
Team pitfalls
1. Partial adoption - only a few developers on the team use TDD
2. Poor maintenance of the test suite - most commonly leading to a test suite
with a prohibitively long running time
3. Abandoned test suite (i.e. seldom or never run) - sometimes as a result of
poor maintenance, sometimes as a result of team turnover
7. REST-API TDD WITH NODE.JS
REST-API: Express and Mongoose
Authorization: Passport
Dependencies Injection: Wagner
Test framework: Mocha
Validation & Assertion: Assert
HTTP Request: Super-Agent
Test And Watch task running: Gulp