TDD stands for Test-Driven Development, or Test-Driven Design. It is the practice of writing a unit test before writing code to satisfy it, in what is known as the Red-Green-Refactor cycle.

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When is unit testing inappropriate or unnecessary? [duplicate]

It seems to be generally assumed (on Stack Overflow at least) that there should always be unit tests, and they should be kept up to date. But I suspect the programmers making these assertions ...
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2answers
95 views

In the BDD paradigm why should the “ubiquitous language” be merely semi-formal and not completely formal?

Here's the relevant quote: A common risk with software development includes communication breakdowns between Developers and Business Stakeholders. BDD uses the specification of desired behavior as ...
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0answers
56 views

Algorithm / Coordinator or Worker / Integrator Distinction

In this article by Jakub Holý on writing maintainable and evolvable tests, the author shares his experience of a course lectured by Kent Beck and that when designing a part of the system Kent would ...
8
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2answers
183 views

Test Driven Development for Complex Games

I'm coding a game in my spare time, but I am mostly still a beginner when it comes to programming. I'm sorry if this question is off topic or if it ends up not being helpful to anyone else, but ...
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2answers
116 views

BDD/TDD - exhaustively testing details which are low-level, but still behaviour

We're looking to concentrate more on testing behaviour (as opposed to every class/method individually) in all our automated tests, as espoused by various high-profile online discussions recently. I ...
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0answers
42 views

Mixing newable and injectable in a Callable

I recently read http://misko.hevery.com/2008/09/30/to-new-or-not-to-new/ which discussed newable vs injectable objects. What would you do if you needed to make a Callable that talks to some service ...
4
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4answers
296 views

Test-Driven Design is not Unit Testing [closed]

Ran across this statement by Martin Fowler circa 2002: Unit testing in XP is often unlike classical unit testing, because in XP you're usually not testing each unit in isolation. You're testing ...
16
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8answers
1k views

What are good unit tests to cover the use case of rolling a die?

I'm trying to get to grips with unit testing. Say we have a die which can has a default number of sides equal to 6 (but can be 4, 5 sided etc.): import random class Die(): def __init__(self, ...
10
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1answer
339 views

Testing strategy for games

I've inherited a web-based educational game. Over the past year I've worked towards stabilizing the code and adding new features. Most of the logic is in the front-end, so back-end unit tests, while ...
147
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16answers
11k views

Why does automated testing keep failing in my company?

We have tried to introduce developer automated testing several times at my company. Our QA team uses Selenium to automate UI tests, but I always wanted to introduce unit tests and integration tests. ...
0
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3answers
84 views

Is it anti-pattern to mix unit test and web test? [duplicate]

It is a language agnostic question, e.g. I have a unit test like # Unit test User user = User.create('john'); assertEquals("User name is john", "john", user.getName()); # Web test start from here ...
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2answers
42 views

Isolated Unit Tests and Fine Grained Failures

One of the reasons often given to write unit tests which mock out all dependencies and are thus completely isolated is to ensure that when a bug exists, only the unit tests for that bug will fail. ...
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2answers
450 views

In which cases Robolectric is a relevant solution? [closed]

As you may now, Robolectric is a framework that provides stubs for Android objects, in order to make tests runnable outside the Dalvik environment. My concern is that, by doing this, one can fake a ...
2
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1answer
106 views

How is the correct way of writing TDD for a void API?

Ok so my scenario is this: I have a third party component that offers an API for communicating with an external system. The method calls for commanding the external system to do stuff, all return ...
4
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2answers
115 views

Is it ok to write “extra” unit tests?

My understanding of how TDD should work is that you write a failing test for the next bit of functionality you want to add to a function or object, code until the test passes and then write the next ...
0
votes
3answers
176 views

Drawback of using static method [duplicate]

For methods that never access instance variable or static variable and they act just like a function (name-spaced) and they are deterministic base on only the input arguments , I want to ask, are ...
5
votes
1answer
142 views

Testing that an attribute does not exist cannot fail when writing tests before code

I have been taught to follow the Red->Greeen->Refactor pattern when doing TDD. There have been situations where this pattern have not been applicable though. For instance, a test to make sure that a ...
48
votes
7answers
3k views

Writing Tests for Existing Code

Suppose one had a relatively large program (say 900k SLOC in C#), all commented/documented thoroughly, well organized and working well. The entire code base was written by a single senior developer ...
1
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1answer
68 views

Question about mocking externals [duplicate]

at company we're developing quite a big project and we're arguing at the testing strategy. The question is: should all of the tests be executed in isolation of external services like database or APIs ...
1
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3answers
147 views

Protected variable & protected method in the era of TDD [closed]

I understand protected method is good for unit testing since you can easily mock by the class by overriding the protected method for the sake of testing. However, protected variable is just a global ...
24
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6answers
2k views

Sense of unit tests without TDD

We have new (quite big) project starting, that we planned to develop using TDD. The idea of TDD failed (many business and non-business reasons), but right now we have a conversation - should we write ...
0
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2answers
66 views

how to write unit test for AND logic gate

I'm learning about unit tests, and have a doubt for a test i want to do, to implement an "AND" logic gate A B A^B 0 0 0 0 1 0 1 0 0 1 1 1 how can i test for a method that works ...
2
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1answer
71 views

Wrapping function in closures to make testable functions

In my nodejs project, I have functions like this for socketio. socket.on('draw', function (data) { socket.broadcast.to(socket.room).emit('draw', data); addEvent(socket, ["draw", data]); }); ...
3
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4answers
183 views

How to identify and run the most relevant automated tests?

Suppose you have a reasonably large codebase (0.5 - 1 msloc) with a large test-suite (6-7hr single-threaded runtime; with a mix of unit-tests and integration-tests built with different tools). You ...
4
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1answer
76 views

Keep or discard tests that use methods now private [duplicate]

When writing object-oriented code from scratch, I try to follow these steps: Write a test that fails. Write a function that makes the test pass. When enough tests and functions are complete, ...
17
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4answers
821 views

How can I use unit tests and TDD to test an app that relies mostly on database CRUD operations?

At work, one of my projects is mostly about taking data passed in from an external client and persisting it in a database. It's a Java enterprise app using JPA and most of our logic revolves around ...
4
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3answers
166 views

Sprint Planning Meetings - determine if a work item is “planned”?

We've been working with Scrum for a while now, generally successfully. However of late, as the pressure has started to mount up we've encountered several situations where items came through planning ...
2
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1answer
159 views

acceptance test driven development in c++

Was put on hold at stack overflow: hopefully it has value here. I want to use a BDD / TDD / ATDD approach in c++. However I really want to emphasize vertical slices of end to end functionality rather ...
1
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2answers
69 views

Creating an Interface To a Language's Standard Library?

In the process of learning test-driven development, I've been introduced to dependency injection and the use of interfaces, and have started using these concepts in my own PHP code in order to make it ...
2
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2answers
173 views

Relationship between TDD and Software Architecture/Design

I'm new to TDD and have been reading the theory since applying it is more complicated than it sounds when you're learning by yourself. As far as I know, the objective is to write test cases for each ...
0
votes
1answer
85 views

How to unit test models in MVC / MVR app?

I'm building a node.js web app and am trying to do so for the first time in a test driven fashion. I'm using nodeunit for testing, which I find allows me to write tests quickly and painlessly. In this ...
8
votes
6answers
493 views

How to use unit tests as a source of information?

A colleague of mine was once at a seminar about agile development, where he heard it is possible to use unit tests as technical documentation. Something like using unit tests as an example of how to ...
9
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3answers
370 views

Designing unit tests for a stateful system

Background Test Driven Development was popularized after I already finished school and in the industry. I am trying to learn it, but some major things still escape me. TDD proponents say lots of ...
0
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1answer
108 views

How do you detect lying Stubs/Mocks?

Consider this piece of code from the PHPUnit manual(I'm using PHP only as an example): class StubTest extends PHPUnit_Framework_TestCase { public function testStub() { // Create a ...
3
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3answers
134 views

Using 2 Constructors: one that injects dependencies and one that instantiates them

I started using TDD for the first time on a project I started recently. I have a few objects with dependencies and structures that look something like this: public class MyClass { private ...
0
votes
1answer
120 views

Is there a name for this technique in testing? [closed]

When I've written tests for some code and want to make sure that it's actually testing what it's supposed to, I'll mess up or remove the code-under-test, and see if the tests fail. If they don't, I've ...
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4answers
172 views

Help in ensuring unit tests are meaningful

I've just written a unit test for this function, which loops through a collection of dates and sets properties equal to true or false depending on whether they're before or after a given comparison ...
66
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19answers
7k views

Why does TDD work?

Test-driven development (TDD) is big these days. I often see it recommended as a solution for a wide range of problems here in Programmers SE and other venues. I wonder why it works. From an ...
2
votes
5answers
436 views

DRY code, DRY tests?

At some point I had to create some class "Class1" and that class needs a method "method". So I have the following: Class1MethodTest: A total of N tests that check the behavior of Class1.method Class1 ...
3
votes
2answers
82 views

How to pick the testing values for parameterized tests for stateless functions?

When writing (parameterized) tests for stateless functions, how do I determine the most ideal set of values to test with? I'm writing a class with mathematical functions in C#, and I want to write ...
29
votes
4answers
1k views

Are there areas where TDD provides a high ROI and other areas where the ROI is so low that it is not worth following? [closed]

Test driven development. I get it, like it. But writing tests does require overhead. So should TDD be used universally throughout the code base, or are there areas where TDD provides a high ROI and ...
2
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2answers
216 views

How to know what to test in TDD? [duplicate]

I've heard about TDD more than one year ago, but until now I didn't manage to get myself started with it. Indeed, one of my greatest doubts is always what to test. The examples given always shows test ...
2
votes
3answers
138 views

How to test state of the object

I have a class DataImport with only two public methods public void fromStream(InputStream inputStream); public ImportCommand getImportCommand(); When I test it I send some test data to fromStream ...
8
votes
3answers
575 views

What is understood under “unit” in unit testing

As I understand in theory under "unit" people mean method (in OOP). But in practice tests which verify some method in isolation are very fragile behaviour tests (verifying not the result but the fact ...
1
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4answers
157 views

Implementing TDD for existing code [duplicate]

I've just been learning Unit Testing and I'm trying to understand how I could incorporate it with a project with existing code. Say I wanted to write tests for a specific class in that project, but ...
2
votes
2answers
221 views

Testing abstract class' behavior

I'm currently refactoring an existing design, which was created without TDD. There is a class hierarchy with one abstract base class and two subclasses. In the original design, these classes were ...
5
votes
7answers
352 views

Test driven development when implementing a flexible length list

According to the commonly used TDD strategy, to implement something, you write a test that fail the code first, write the simplest code, refactor, and then repeat. I am trying to imagine this scenario ...
12
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5answers
827 views

Types of unit tests based on usefulness

From value point of view I see two groups of unit tests in my practice: Tests that test some non-trivial logic. Writing them (either before implementation or after) reveals some problems/potential ...
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2answers
750 views

Testing ASP.NET .aspx and .ascx code behind files

I am wondering how to test .aspx.cs and .ascx.cs code behind. Can I use unit testing and if so how? Are there alternatives that will help test the functions in the code behind files? I don't know how ...
123
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6answers
54k views

What is the difference between BDD and TDD?

I have been learning writing test cases for BDD using specflow. If I write comprehensive tests with BDD is it necessary to write TDD test separately? Is it necessary to write test cases for both TDD ...