Why the first instruction we learn to program should be the last to use.
Nobody uses GOTO instruction anymore and few programming languages still support it.
We have matured and confirmed spaghetti code is unmaintainable and error prone. Structured Programming solved that problem years ago.
We got rid of the sentence thanks to Edsger Dijkstra’s incredible paper: Go To Statement Considered Harmful.
Next evolution step will be removing most IF statements
IFs/Cases and Switches are GOTOs disguised as structured flow.
Our tool will be Object Oriented Programming principles.
Incomplete objects cause lots of issues.
Problems
- Mutability
- Incomplete objects
- Concurrency inconsistencies between creation and essence setting.
- Setters
Solutions
- Pass the object’s essence on creation
Examples
- Some persistence frameworks in static typed languages require an empty constructor.
Exceptions
- Stateless objects. Always better solution than static class methods.
Sample Code
Wrong
Right
Detection
Any linter can warn this (possible) situation.
Tags
- Essence
- Incomplete
- Mutable
Conclusion
Always create complete objects. Make their essence immutable to endure through time. Every object needs its essence to be a valid one since inception.
Writing a class without its contract would be similar to producing an engineering component (electrical circuit, VLSI (Very Large Scale Integration)…
The code smells bad. Let’s see how to change the aromas.
TL;DR: A Compilation of bad smells in code.
In this series, we will see several symptoms and situations that make us doubt the quality of our developments.
We will present possible solutions.
Most of these smells are just clues of something that might be wrong. They are not rigid rules.
Code Smells
Your objects are a bunch of public attributes without behavior.
Protocol is empty (with setters/getters).
If we ask a domain expert to describe an entity he/she would hardly tell it is ‘a bunch of attributes’.
Problems
Solutions
1) Find Responsibilities.
2) Protect your attributes.
3) Hide implementations.
4) Delegate
Examples
- DTOs
Sample Code
Wrong
Right
Detection
Detection can be automated with sophisticated linters ignoring setters and getters and counting real behavior methods.
Also Known as
- Data Class
Tags
- Anemic
- OOP as Data
- Encapsulation
- Setters/Getters
- Mutability
More info
This…
Const declares something to be constant. Can it mutate?
TL;DR: Don’t rely on languages cheating about directives.
Problems
- Unexpected side effects
- Accidental complexity
Solutions
- Use better languages
- Use spread operator
Sample Code
Wrong
Right
Detection
Since this is a “language feature”, we can explicitly forbid it.
Tags
- Mutability
- JavaScript
Conclusion
We should always favour immutability on our designs and take extra care with side effects.
More Info
Credits
Thank you,Oliver Jumpertz for this tip.
Correctness is clearly the prime quality. If a system does not do what it is supposed to do, then everything else about it matters little.
Bertrand Meyer
This article is…
Do not perform more than requested.
TL;DR: Unless you need atomicity, do not perform more than one task.
Problems
- Coupling
- Single Responsibility Principle violation
- Readability
- Low Cohesion
- Testability
Solutions
- Break the function
Sample Code
Wrong
Right
Detection
Functions including “and” are candidates. However, we need to check them carefully since there might be false positives.
Tags
- Readability
- Naming
Conclusion
We should avoid doing more than needed, and our functions should be both minimal and atomic.
More Info
Credits
This smell was inspired by
If it takes more than a sentence to explain what you are doing, it’s almost always a sign that what you are doing is too complicated.
Sam Altman
This article is part…
First International Test Driven Development took place on July 10th.
In this series, I will include every talk together with my notes and further reading.
Hopefully, a lot of readers will watch and rewatch the talks, as they are worth several reviews.
Let’s continue…
Bio
Daniel Moka is a TDD enthusiast and boundary pusher who has a strong passion for crafting quality software while using education to change the world. He has a solid background in building enterprise solutions using the .NET stack deployed to cloud environments. …
First International Test Driven Development took place on July 10th.
In this series, I will include every talk together with my notes and further reading.
Hopefully, a lot of readers will watch and rewatch the talks, as they are worth several reviews.
Let’s continue…
Bio
Mario has been a software professional for more than a decade. He also conducted research in the field of Software Engineering, which allowed him to graduate as a PhD in Computer Science. …
First International Test Driven Development took place on July 10th.
In this series, I will include every talk together with my notes and further reading.
Hopefully, a lot of readers will watch and rewatch the talks, as they are worth several reviews.
Let’s continue…
Bio
Jov is a software craftsman and TDD practitioner, working on Android for around 10 years now. He has a big passion for clean code, TDD, software craftsmanship, and knowledge sharing. He co-organized the DevTernity conference.
TL;DR: TDD is hard to master, with good guidance we can get excellent solutions.
Talk
My Personal notes
- TDD is not a testing strategy…
First International Test Driven Development took place on July 10th.
In this series, I will include every talk together with my notes and further reading.
Hopefully, a lot of readers will watch and rewatch the talks, as they are worth several reviews.
Let’s continue…
Bio
Liz Keogh is a Lean and Agile consultant based in London. She is a well-known blogger and international speaker, a core member of the BDD community and a passionate advocate of the Cynefin framework and of Wardley Mapping. She has a strong technical background with over 20 years’ experience in delivering and coaching others to deliver…
