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.

learn more… | top users | synonyms (2)

6
votes
4answers
369 views

Testing To Prevent Cascading Bugs

Yesterday, Twitter was hit with a "Cascading Bug" as described in this blog post: A “cascading bug” is a bug with an effect that isn’t confined to a particular software element, but rather its ...
6
votes
2answers
1k views

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 ...
6
votes
2answers
470 views

Ruby Koans: depth and usefulness? [closed]

Several people have suggested Ruby Koans to me over just following a book, and this seems like a much better prospect. As there is no question regarding the entirety of Ruby Koans, what do SO users ...
5
votes
4answers
589 views

How to Write Unit Tests When One Fix Will Make Many Failing Tests Pass?

I have two test cases to test a fix to code that is using the wrong criteria for selecting objects from a collection: Given one object in the collection matching the bad criteria, ensure that no ...
5
votes
2answers
1k views

A weakness of the TDD method?

This is in summary the TDD method: Write a test check if thes test fails write production code run test I think that TDD as presented works only in ideal circumstances. I'll take a simple ...
5
votes
5answers
1k views

If we have TDD and BDD why do we need QA for? [duplicate]

If we have TDD and BDD why do we need QA for? Isn't the job of the developer to write bugs or failing tests? If this is true how a QA fit in? Thanks.
5
votes
5answers
361 views

Can we add methods which is easier for assertion in test and which is only used in tests when TDD?

Here let me take a simple parking boy example. A parking boy can manage several parking lots, and when a car comes, he will park the car into some parking lot and can also help to un-park the car. ...
5
votes
2answers
434 views

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 ...
5
votes
5answers
8k views

Understanding unit tests/TDD for ASP.NET webforms [closed]

I'm the lead programmer at a small software firm (currently 4 developers including myself), we develop bespoke ASP.NET WebForms applications for businesses. I joined there in 2010 just after ...
5
votes
3answers
578 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 ...
5
votes
10answers
521 views

Is is possible to do TDD without a test tool?

We want to implement a fairly rough outline of test driven development which involves a developer asking themselves the tests at each stage of the development process. I have read here that its ...
5
votes
2answers
596 views

Tools that can catch “fake coverage”?

Hypothetical scenario: codebase is exercised by unit tests run by a TeamCity build-bot, that also uses the built-in dotCover tool to provide coverage metrics. The build will fail if less than X% of ...
5
votes
2answers
434 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 ...
5
votes
5answers
355 views

An alternative to requiring red in TDD: reverting code change?

According to this answer to this question, a good reason for always starting with a failing test ("Red") is to make sure that the test is working and that the code that will be written is what makes ...
5
votes
5answers
404 views

TDD: Write a separate test for object initialization or relying on other tests exercising it

This seems to be the common pattern that's emerging in some of the tests I've worked on lately. We have a class, and quite often this is legacy code whose design can't be easily altered, which has a ...
5
votes
2answers
1k views

TDD with repository pattern

In my new project, I decided to try with TDD. And in very beginning I encountered a problem. First thing that I want to do in my application is to give ability to read data from data source. For this ...
5
votes
6answers
483 views

Sporadic unittests or TDD?

I've read some basics about unit tests and TDD, but I find it hard to convince myself why TDD can have an advantage over only selected unittests. I've read common arguments for TDD, but don't see the ...
5
votes
1answer
178 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 ...
5
votes
4answers
287 views

Type mocking frameworks does not change coding practices from testability point?

Many people recommend that we should code against interfaces and avoid statics for testability. Interfaces are not just for testability, they are sometimes a requirement. But sometimes we introduce ...
5
votes
4answers
1k views

Unit testing data access objects

I have recently started using test-driven development and unit testing, and it has paid off immensely in the areas where I have aplied it. One area that it has been helpful in is database access. When ...
5
votes
5answers
420 views

Is it possible to be agile without use cases and tests?

Rhetoric teaches us that the answer is probably yes. However I feel that we would no longer relate to the vast majority of Agile success stories. I think that my upper management read the benefits ...
5
votes
5answers
447 views

TDD: Where should I start?

I've read a lot about TDD and I've tried to develop using TDD without success ... I always stop staring at the screen... I've learned that I should not write tests for methods or class. I should ...
5
votes
2answers
1k views

Unit testing behaviours without coupling to implementation details

In his talk TDD, where did it all go wrong, Ian Cooper pushes Kent Beck's original intention behind unit testing in TDD (to test behaviours, not methods of classes specifically) and argues for ...
5
votes
7answers
531 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 ...
5
votes
4answers
195 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) { ...
5
votes
1answer
209 views

What is a “behavior rich object” and why would it be advantageous?

I am referring to the article Mocks aren't Stubs by Martin Fowler. When naming cases when he think "mockist" TDD will be advantageous, he said It's particularly worth trying if you are having ...
5
votes
3answers
175 views

Should unit tests always overlap

This is a test design question. I have a class 'handler' that accepts a 'validator' that checks some business logic on what's passed to the handler. I made the unit tests for the validator and now ...
5
votes
2answers
1k views

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? ...
5
votes
2answers
283 views

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 ...
5
votes
1answer
544 views

Unit testing of “workflow” methods

We are currently developing a public API for our app. The methods on this public API are mostly putting together functionality in different corners of the system. An example would be: (names have been ...
5
votes
1answer
347 views

How to test network connectivity API using TDD?

I'm currently trying to add TDD on my workflow. I fail to create tests where I can easily test a library that requires remote connections. More precise, my program uses snmp4j library. Currently I'm ...
5
votes
2answers
202 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 ...
5
votes
1answer
824 views

How do you write tests for methods that interact with data in system files?

I'm trying to be proactive about writing an iOS app in a test-driven manner. However, I'm stumped as to how to test a method that is to interact with real system files. For those familiar with iOS, ...
5
votes
2answers
1k views

How to organize unit/integration test in BDD

So finally after reading a lot, I have understood that the difference between BDD and TDD is between T & B. But coming from basic TDD background, what I used to was, first write unittest for ...
5
votes
2answers
546 views

Testing-related methodologies except TDD/BDD [closed]

Are there any testing-related methodologies except TDD/BDD? I see a lot of people who practice their own testing approaches (e. g., see Ayende post), but I don't see any formalization for it, no ...
5
votes
4answers
303 views

Unit Testing and .Net

Coming from a native development background, I'm used to my unit test runners outputting the file and line that caused the test failure. This allowed me to run the tests as a post-build step, and if ...
5
votes
1answer
622 views

Test-Driven Development with plain C: manage multiple modules

I am new to test-driven development, but I'm loving it. There is, however, a main problem that prevents me from using it effectively. I work for embedded medical applications, plain C, with safety ...
5
votes
1answer
827 views

Node.JS testing with Jasmine, databases, and pre-existing code

I've recently built the start of a core system which is likely going turn into a monster product. I'm building the system with node.js, and decided after I got a small base built, that It'd be a ...
4
votes
8answers
607 views

Emphasizing the importance of TDD to customers

The importance of TDD needs to be propagated but there's always a gap in the project timeline and time needed for developing a TDD project. Customers usually do not understand the importance of code ...
4
votes
4answers
768 views

How to test a method which is not as much as a unit, because it is more of a 'orchestrator' / 'process' / 'controller' / 'coordination' class [duplicate]

I want to test a method which is not as much as a unit, because it is more of a 'orchestrator' / 'process' / 'controller' / 'coordination' class. This is the case: I have four unit tested classes: ...
4
votes
5answers
229 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 ...
4
votes
4answers
372 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 ...
4
votes
8answers
1k views

How to measure that a team is doing Test Driven Development

My team is considering a department goal of doing Test Driven Development next (fiscal) year. TDD sounds good and my manager is on board. The only problem is measurement. Our company rules require ...
4
votes
4answers
218 views

How can I create Assert.AreEqual(myobject,somevariable) a test in TDD before writing production code?

Im researching TDD, I'm not really sure how to write a test before I have written production code. The problem is that TDD states that you make assertions and then write your code so that these ...
4
votes
2answers
204 views

Test Driven Development when the specifications change

These days, it's fairly common for me to be tasked to make a change that actually breaks the prior spec. I know that one of the major ideas behind TDD is to have a suite that verifies all your changes ...
4
votes
4answers
405 views

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= ...
4
votes
4answers
918 views

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 ...
4
votes
3answers
476 views

How to conduct a 3 days training on current techniques like TDD and CI [closed]

I am tasked to conduct a training for an upcoming team of 20 Java developers for a new project. The project owner wants us to use state of the art development techniques like TDD and CI. The ...
4
votes
5answers
945 views

Are there any cases when one should not use Test Driven Development? [duplicate]

Is it recommended that TDD be always practiced in a project, or are there cases when it should be avoided? Should we all adopt TDD? Is it standard practice in major software companies?
4
votes
4answers
243 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 ...