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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In TDD, if I write a test case that passes without modifying production code, what does that mean?

These are Robert C. Martin's rules for TDD: You are not allowed to write any production code unless it is to make a failing unit test pass. You are not allowed to write any more of a unit test than ...
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What's the next logical TDD move in this learning example?

I'm inching my way up the TDD ladder and I've got to a point where I'd like to get advice on the "next move". I realize there might not be a single answer here, so any logical suggestion would be ...
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Should I use TDD and BDD if my project is changing fast?

I have my own little project I am creating using RoR, I plan it to have small-medium load. With no doubt I started with BDD and TDD (Cucumber and RSpec to be exact, but I am also experienced with ...
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Is there a modern replacement for a mutation testing tool like Jester for Java?

“Why just think your tests are good when you can know for sure? Sometimes Jester tells me my tests are airtight, but sometimes the changes it finds come as a bolt out of the blue. Highly ...
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Do I need to learn python first to understand the part 2 of the book Test Driven development?

It seems like Python is used as a coding language for part 2 of Kent Beck's book Test Driven Development. I have read the first part of that book and started appreciating the value of TDD . First part ...
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Can I start with a passing unit test?

Uncle Bob's rules for TDD are specified here. You are not allowed to write any production code unless it is to make a failing unit test pass. You are not allowed to write any more of a unit test ...
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4answers
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Why is test driven development missing from Joel's Test?

I was reading this blog by Joel Spolsky about 12 steps to better code. The absence of Test Driven Development really surprised me. So I want to throw the question to the Gurus. Is TDD not really worth ...
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Unit testing on visualization (3D graphics) frameworks

This is a follow up to this question. There I was asking how to do unit testing when you have a library of scientific algorithms. I have a similar problem now but with a different project. I'm ...
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Should I write a test to prove that deleting code fixes a bug?

Occasionally I'll run into the situation where fixing a bug requires that I delete a section of code. The TDD purist would (I assume) advocate writing a failing test, deleting the code, then watching ...
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Functional testing and Acceptance testing leading to redundant code

What I know is: A Functional test aims to test a single component (like a WebApp's Controller) from the point of view of the developer. => Did I achieve all the requirements to make it work well? ...
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organising classes / folder structure for TDD-based development

Due to test-driven development, one ends up with many classes doing just one thing. It is quite a headache just to see where such classes would be placed inside the folder structure. First of all, ...
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Should I refactor my unit tests when I extract a class out of the System Under Test?

I wrote this class that does a few things (perhaps this is a violation of the Single Responsibility Principle). I realize now that some other part of the project needs a piece of that logic and the ...
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8answers
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Alternative to “Passing/Broken build” indicator?

When having a continuous integration executing the tests at each commit, a common best practice is to have all the tests passing at all times (aka "do not break the build"). I find some problems with ...
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2answers
985 views

Helper static methods in TDD

I am creating an application which will be testable(unit + integration). In this application I have a FileHelper static class, public static class FileHelper { public static void ...
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373 views

Write tests for unit tests in TDD?

In an answer to another question, I suggested creating a randomized value for input to a specific method. In my experience this has been useful for making tests more readable and it lets you skip the ...
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How to setup TDD environment

In TDD, is it good practice to keep the tests in the same directory as the code its testing or is it better separate the tests in either a different directory or a separate project. Would it be the ...
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21answers
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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. ...
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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 ...
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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 ...
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Unit Test Friendly Domain Driven Design

Many of the readings I've done on DDD, both in books and online, seem to represent code that, often times, is difficult or impossible to unit test. For example, there are numerous samples with static ...
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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 ...
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3answers
463 views

How much to test in TDD?

I am newbie to TDD (writing first project following TDD practices). I have fairly basic interface IProfiler and an implementation Profiler. interface IProfiler { bool IsBusy {get;} long Elapsed ...
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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 ...
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Is it okay to mock multiple objects in one class?

For developers with extensive experience using mocks, is it okay to mock multiple objects in one class (ie satisfy multiple interfaces) or is this not recommended? I am wondering because mocks are ...
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How would type errors be detected while creating mocks in a dynamic language?

The problem occurs while doing TDD. After a couple of test pass, the return types of some class/module change. In a statically typed programming language, if a previous mocked object was used in the ...
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5answers
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How to understand and debug legacy software? [duplicate]

Possible Duplicate: I’ve inherited 200K lines of spaghetti code — what now? Not long ago my company placed me in a team that deals with some of the most complex bugs that are in production. ...
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1answer
391 views

TDD and test automation in applications heavily dependent on databases and user input [closed]

Recently I have been reading online about eXtreme programming and agile practices. I wish to adapt them. However most of my code is all in PHP which is the normal CRUD type web applications. Moreover ...
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Requesting quality analysis test cases up front of implementation/change

Recently I have been assigned to work on a major requirement that falls between a change request and an improvement. The previous implementation was done (badly) by a senior developer that left the ...
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221 views

Review tests first

I am going to adopt TDD in our team and one of the ideas I have is to review tests first. So one would write interfaces, mocks, and tests first, submit them for a code review and once interfaces and ...
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3answers
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Does TDD lead to the good design? [duplicate]

I'm in transition from "writing unit tests" state to TDD. I saw as Johannes Brodwall creates quite acceptable design from avoiding any of architecture phase before. I'll ask him soon if it was real ...
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4answers
368 views

How to get initial API right using TDD?

This might be a rather silly question as I am at my first attempts at TDD. I loved the sense of confidence it brings and generally better structure of my code but when I started to apply it on ...
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1answer
411 views

In which cases Robolectric is a relevant solution?

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 ...
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TDD in JavaScript [closed]

I'm about to participate in a Coding Kata and I would like to do it in JavaScript. What tools and libraries do I need for TDD in JavaScript?
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Test driven vs Business requirements constant changing

One of the new requirement of our dev team set by the CTO/CIO is to become test driven development, however I don't think the rest of the business is going to help because they have no sense of ...
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How do you handle increasingly long compile times when working with templates?

I use Visual Studio 2012 and he have cases where we added templates parameters to a class "just" in order to introduce a "seam point" so that in unit-test we can replace those parts with mock objects. ...
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2answers
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Unit test and Code Coverage of Ant build scripts

In our development environment We have more and more build scripts for ant to perform the build tasks for several different build jobs. These build scripts sometimes become large and do a lot of ...
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How to TDD test that objects are being added to a collection if the collection is private?

Assume that I planned to write a class that worked something like this: public class GameCharacter { private Collection<CharacterEffect> _collection; public void Add(CharacterEffect e) ...
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How can I test database access methods in Java? [closed]

I want to write a test for a method that accesses a database such as following. public class MyClass{ public String getAddress(Int id){ String query = "Select * from Address where ...
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3answers
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What if I can't make my unit test fail in “Red, Green, Refactor” of TDD?

So let's say that I have a test: @Test public void MoveY_MoveZero_DoesNotMove() { Point p = new Point(50.0, 50.0); p.MoveY(0.0); Assert.assertAreEqual(50.0, p.Y); } This test then ...
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What to do when TDD tests reveal new functionality that is needed that also needs tests?

What do you do when you are writing a test and you get to the point where you need to make the test pass and you realize that you need an additional piece of functionality that should be separated ...
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1answer
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Is wrapping a third party code the only solution to unit test its consumers?

I'm doing unit testing and in one of my classes I need to send a mail from one of the methods, so using constructor injection I inject an instance of Zend_Mail class which is in Zend framework. Now ...
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Are injectable classes allowed to have constructor parameters in DI?

Given the following code: class ClientClass{ public function print(){ //some code to calculate $inputString $parser= new Parser($inputString); $result= ...
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5answers
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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 ...
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2answers
217 views

Returning a mock object from a mock object

I'm trying to return an object when mocking a parser class. This is the test code using PHPUnit 3.7 //set up the result object that I want to be returned from the call to parse method ...
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4answers
178 views

How to implement isValid correctly?

I'm trying to provide a mechanism for validating my object like this: class SomeObject { private $_inputString; private $_errors=array(); public function __construct($inputString) { ...
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5answers
698 views

“TDD is about design, not verification”; concretely, what does that mean?

I've been wondering about this. What do we exactly mean by design and verification. Should I just apply TDD to make sure my code is SOLID and not check if it's external behaviour is correct? Should ...
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3answers
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Introduce unit testing when codebase is already available [duplicate]

Possible Duplicate: Best practices for retrofitting legacy code with automated tests I've been working on a project in Flex for three years now without unit testing. The simple reason for ...
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1answer
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How to unit test image processing code?

I'm working in image processing (mainly OCR) and I wonder how I should integrate unit tests in my development. I'm already using unit tests for more "common" type of code but when dealing with image ...
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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 ...
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Unit testing and Test Driven Development questions

I'm working on an ASP.NET MVC website which performs relatively complex calculations as one of its functions. This functionality was developed some time ago (before I started working on the ...