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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Should I intentionally break the build when a bug is found in production?

It seems reasonable to me that if a serious bug is found in production by end-users, a failing unit test should be added to cover that bug, thus intentionally breaking the build until the bug is ...
147
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16answers
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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. ...
132
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6answers
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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 ...
95
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10answers
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TDD vs. Productivity

In my current project (a game, in C++), I decided that I would use Test Driven Development 100% during development. In terms of code quality, this has been great. My code has never been so well ...
73
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13answers
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When is it appropriate to not unit test?

I work in a small company as a solo developer. I'm the only developer at the company in fact. I have several (relatively) large projects I've written and maintain regularly, and none of them have ...
70
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20answers
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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 ...
68
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16answers
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TDD negative experience [closed]

What is a negative side of your TDD experience? Do you find baby steps (the simplest fix to make test green) annoying and useless? Do you find no-value tests (when test has sense initially but in ...
67
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16answers
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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 ...
56
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12answers
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New to TDD. Should I avoid private methods now?

I'm just now learning TDD. It's my understanding that private methods are untestable and shouldn't be worried about because the public API will provide enough information for verifying an object's ...
49
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7answers
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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 ...
48
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16answers
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Why not write all tests at once when doing TDD?

The Red - Green - Refactor cycle for TDD is well established and accepted. We write one failing unit test and make it pass as simply as possible. What are the benefits to this approach over writing ...
45
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11answers
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I don't understand how TDD helps me get a good design if I need a design to start testing it

I'm trying to wrap my head around TDD, specifically the development part. I've looked at some books, but the ones I found mainly tackle the testing part - the History of NUnit, why testing is good, ...
43
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14answers
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Does TDD really work for complex projects?

I’m asking this question regarding problems I have experienced during TDD projects. I have noticed the following challenges when creating unit tests. Generating and maintaining mock data It’s hard ...
43
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6answers
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How to deal with static utility classes when designing for testability

We are trying to design our system to be testable and in most parts developed using TDD. Currently we are trying to solve the following problem: In various places it is necessary for us to use static ...
42
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9answers
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What are the disadvantages of test-first programming?

It's all the rage nowadays. "Everyone" recommends it. That in and of itself makes me suspicious. What are some disadvantages you have found when doing test-first (test-driven) development? I'm ...
40
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9answers
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How to test the tests?

We test our code to make it more correct (actually, less likely to be incorrect). However, the tests are also code -- they can also contain errors. And if your tests are buggy, they hardly make your ...
38
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11answers
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What are the disadvantages of automated testing?

There are a number of questions on this site that give plenty of information about the benefits that can be gained from automated testing. But I didn't see anything that represented the other side of ...
37
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9answers
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Do we need Logging when doing TDD?

When doing the Red, Green & Refactor cycle we should always write the minimum code to pass the test. This is the way I have been taught about TDD and the way almost all books describe the process. ...
36
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14answers
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If you had two projects with the same specification and only one was developed using TDD how could you tell?

I was asked this question in an interview and it has been bugging me ever since. You have two projects, both with the same specification but only one of these projects was developed using Test ...
36
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9answers
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Can you be Agile without doing TDD (test driven development)?

Is is possible to correctly call yourself (or your team) "Agile" if you don't do TDD (Test-Driven Development)?
36
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How do people doing TDD handle loss of work when doing major refactoring

For a while I have been trying to learn to write unit tests for my code. Initially I started out doing true TDD, where I wouldn't write any code until I'd written a failing test first. However, I ...
36
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7answers
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Is it sufficient to use acceptance and integration tests instead of unit test?

Short introduction to this question. I have used now TDD and lately BDD for over one year now. I use techniques like mocking to make writing my tests more efficiently. Lately I have started a ...
35
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6answers
6k views

Good example of complex code using TDD [closed]

What would be a good example of the use of TDD in large, real-life, complex, projects? All the examples I've seen so far are toy projects for the purpose of a book or a paper... Can you name an ...
34
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9answers
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How baby are your baby-steps in TDD?

Today we were training TDD and found the following point of misunderstanding. The task is for the input "1,2" return sum of numbers which is 3. What I have written (in C#) was: numbers = ...
34
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10answers
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Is unit testing or test-driven development worthwhile?

My team at work is moving to Scrum and other teams are starting to do test-driven development using unit tests and user acceptance tests. I like the UATs, but I'm not sold on unit testing for ...
33
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10answers
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TDD - is it just about unit tests? [duplicate]

Do I understand it right that classical TDD is just about unit tests? Don't understand me wrong: I know the difference between TDD and just unit testing. I am asking whether it is correct to use ...
33
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2answers
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How should C++ Unit Test code be organized for maximum Unit Test efficiency?

This question is not about Unit Testing Frameworks. This question is not about writing Unit Tests. This question is about where to put the UT code written and how/when/where to compile and run it. ...
30
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6answers
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How should you TDD a Yahtzee game?

Let's say you're writing a Yahtzee game TDD style. You want to test the part of the code that determines whether or not a set of five die rolls is a full house. As far as I know, when doing TDD, you ...
29
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7answers
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Unit testing newbie team needs to unit test

I'm working with a new team that has historically not done ANY unit testing. My goal is for the team to eventually employ TDD (Test Driven Development) as their natural process. But since TDD is ...
29
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5answers
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How do you convince management to “invest” in unit tests?

How did you convince your manager to let you unit test? By "use", I mean being allowed to develop, check-in to source control and maintain the unit tests over time, etc. Typical management ...
29
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4answers
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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 ...
29
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2answers
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What are the London and Chicago schools of TDD?

I’ve been hearing about the London style vs. Chicago style (sometimes called Detroit style) of Test Driven Development (TDD). Workshop of Utah Extreme Programming User's Group: Interaction-style ...
28
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7answers
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Difference Between Unit Testing and Test Driven Development

From reading the descriptions, I understand that in TDD tests are done prior to writing the function and in Unit Testing, its done afterwards. Is this the main difference, or the two terms can't even ...
28
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5answers
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Test driven development - convince me! [closed]

I know some people are massive proponents of test driven development. I have used unit tests in the past, but only to test operations that can be tested easily or which I believe will quite possibly ...
27
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11answers
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Do I need to test everything?

I'm going to start my first real project in Ruby on Rails, and I'm forcing myself to write TDD tests. I don't see real advantages in writing tests, but since it seems very important, I'll try. Is it ...
26
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11answers
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Writing the minimum code to pass a unit test - without cheating!

When doing TDD and writing a unit test, how does one resist the urge to "cheat" when writing the first iteration of "implementation" code that you're testing? For example: Let's I need to calculate ...
26
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5answers
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Why is it often said that the test cases need to be made before we start coding? [duplicate]

Why is it often said that the test cases need to be made before we start coding? What are its pros and what the cons if we don't listen to this advice? Moreover, does that advice refer to black box ...
26
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5answers
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What is an integration test exactly?

My friends and I have been struggling to classify exactly what is an integration test. Now, on my way home, I just realised, that every time I try to give a real world example of an integration ...
25
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5answers
3k views

I want to start using TDD. Any tips for a beginner? [closed]

I never used an automated test mechanism in any of my projects and I feel I'm missing a lot. I want to improve myself, so I have to start tackling some issues I've been neglecting like this and trying ...
24
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11answers
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How do we make unit tests run fast?

We have reached the point in our project where we have almost a thousand tests and people have stopped bothering with running them before doing a check in because it takes so long. At best they run ...
24
votes
6answers
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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 ...
23
votes
4answers
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TDD - Outside In vs Inside Out

What is the difference between building an application Outside In vs building it Inside Out using TDD? These are the books I read about TDD and unit testing: Test Driven Development: By Example ...
23
votes
8answers
2k views

Are “TDD Tests” different to Unit Tests? [duplicate]

I read Stephen Walther's article about Test Driven Development (TDD) and unit testing. I think it was an excellent article. The author makes a distinction between what he calls "TDD Tests" and unit ...
21
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5answers
2k views

Do unit tests sometimes break encapsulation? [duplicate]

I very often hear the following: "If you want to test private methods, you'd better put that in another class and expose it." While sometimes that's the case and we have a hiding concept inside our ...
21
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7answers
847 views

Should I have unit tests for known defects?

If my code contains a known defect which should be fixed, but isn't yet, and won't be fixed for the current release, and might not be fixed in the forseeable future, should there be a failing unit ...
21
votes
10answers
1k views

Automated Testing: Explaining its Business Value

To start I don't think this is a repeat of other questions on unit testing. What I'm looking for help with is articulating its value to a team of programmers, analysts, managers and testers. By ...
20
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8answers
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What are the disadvantages of writing code before writing unit tests?

I have always seen the recommendation that we should first write unit tests and then start writing code. But I feel that going the other way is much more comfortable (for me) - write code and then the ...
20
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2answers
617 views

How do I create an environment where fixing tests is seen as a priority?

I am a software engineer at a medium sized company. We have a fairly robust testing platform running on TeamCity. It does unit tests on every checkin, and a daily unit test/BVT run. The problem is ...
20
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9answers
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Should we test all our methods?

So today I had a talk with my teammate about unit testing. The whole thing started when he asked me "hey, where are the tests for that class, I see only one?". The whole class was a manager (or a ...
19
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5answers
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What are the design principles that promote testable code? (designing testable code vs driving design through tests)

Most of the projects that I work on consider development and unit testing in isolation which makes writing unit tests at a later instance a nightmare. My objective is to keep testing in mind during ...