Test-Driven Development (TDD) by Example | Unity and C# | Tutorial

Table of content:
- 00:11 - What is TDD
- 00:56 - The 3 Laws of TDD
- 01:35 - The 3 steps of TDD (Red-Green-Refactor)
- 02:18 - Example

I wanna make sure that TDD isn't something that makes fun. TDD can be really really boring. It's a discipline like brushing your teeth twice a day and it may seem useless at first glance. TDD is still critiziced by many - even experienced - developers. But on the long-run the pros surpass the cons:

- Since you always write the test first, it automatically ensures that your code is testable.
- You only implement as much code as needed to pass the current failing test. That guarantees 100% coverage of your code.
- In general TDD leads to a simpler implementation because you always concentrate on one single thing and make sure to only implement the stuff you really need in your game.

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[Tocha_official]

There is one more cons for TDD in game dev: We usually need abstraction and dependency inversion to mock the dependencies. While in game dev, we usually use composition rather than inheritance . And we don't have any control on a GameObject's constructor to implement DI.

[kekddd]

I think you've created a fantastic demonstration of what real TDD looks like. Thanks for this.

[Omega]

Love the pause in music at 2:32 xD
your videos are very well made man thanks for the amazing content! liked and subscribed

[seanregehr]

"Should_Calculate_Points()" Great video!

[thygrrr]

What I hate about these is... 99% of the game code is NOT calculating points and NOT some sort of i/o. most of a game is complex real time behaviours. How do you test whether a ball bounces correctly? It's just one monobehaviour, with no public API.

[damienpol]

Sounds great in theory but unless you know every framework like the back of your hand, you don't actually know what you can do until you try to make it.

[SiRTK]

Thanks for this! It's was simplest to understand how to build a TDD function!

[MarkMcDonald_Alpha]

Thanks for this, great practical example of TDD.

[hmhmhm]

This was a really great video! So well put together. I would love for you to continue the Unity testing series. Is there a way to more quickly generate test cases or do I have to crunch the numbers and manually enter each test case?

[DudeWatIsThis]

This is fantastic, but it is generic TDD.

Has anyone figured out how to automate tests for stuff that actually involves the cluster-F that are MonoBehaviours? Stuff like moving a character around and test that it works.

Until we do, the TDD coverage will be 30-40% in games - maximum.

[sergey_molchanovsky]

Great work!
Please add a lesson how to use NSubstitute.

[modernator]

Thanks for great tutorial! However how do I test async jobs like async function or coroutine, and internal game logics such as login process or checking reward on killing enemy like stuffs?

[daryladhityahenry]

Hi.. first, thanks for the tutorial, you explain it and demonstrated it so well.

But, I have question: Is there no faster way to check the test result, like swift iOS, java, or even typescript tdd, it just need to code, press shortcut to test run, and get the result from command line within the IDE? I find it quite takes time to go back and forth from IDE to Unity, and so on. Because unit test should be fast right? But, what I see from the video is: because we're using unity, we must wait for unity check for the saved code, refreshed the method list, then we must tap run test... So, within that cycle alone already takes to much time for unit test. Right?

I really hope there's another way to do this. Is there any?

Thanks..

[lcs_mas]

You are testing too much behavior in only one test. Test should be a documentation, documenting each behavior in isolation.