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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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 ...
49
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7answers
4k 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 ...
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1answer
72 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 ...
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3answers
176 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 ...
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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 ...
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2answers
72 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 ...
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1answer
84 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
197 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
78 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, ...
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4answers
985 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
181 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
317 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 ...
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2answers
73 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 ...
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2answers
183 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
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1answer
115 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 ...
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6answers
528 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 ...
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3answers
438 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 ...
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1answer
113 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 ...
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3answers
137 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 ...
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1answer
123 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
200 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 ...
2
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5answers
492 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
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2answers
98 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
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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 ...
3
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2answers
293 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
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3answers
147 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 ...
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3answers
584 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 ...
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4answers
220 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
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2answers
295 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 ...
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7answers
372 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 ...
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5answers
855 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
1k 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 ...
4
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5answers
368 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?
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1answer
271 views

If TDD is design, how do you know your TDD is well designed? [duplicate]

Given a large group (50+) of programmers: All given the same problem, All using Test-Driven Development (TDD), All pair programming, All doing group-based code review, I have personally seen the ...
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5answers
877 views

Why write tests for code that I will refactor?

I am refactoring a huge legacy code class. Refactoring (I presume) advocates this: write tests for the legacy class refactor the heck out of the class Problem: once I refactor the class, my ...
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12answers
6k views

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 ...
3
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2answers
389 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 ...
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2answers
141 views

Characterization in Testing: Unit test or Functional test [duplicate]

So I'm trying to push for more automated testing in my company, which focus a lot on prototype and proof of concept systems. We currently use Google Test for unit testing. This tests specific test ...
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9answers
3k views

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 ...
9
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2answers
297 views

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 ...
7
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1answer
369 views

Test Driven Development Code Order

I am developing my first project using test driven development. I am using Zend Framework and PHPUnit. Currently my project is at 100% code coverage but I am not sure I understand in what order I am ...
16
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6answers
884 views

From a TDD perspective, am I a bad person if I test against a live endpoint instead of a mock?

I follow TDD religiously. My projects typically have 85% or better test coverage, with meaningful test cases. I do a lot of work with HBase, and the main client interface, HTable, is a real pain ...
1
vote
1answer
89 views

TDD verifying dependency method invoked correctly

I am trying to follow TDD in my proj but I can't get my head around how to verify I am calling a dependency correctly or even if I should be trying to verify it. Here's the requirement: Write an ...
0
votes
1answer
172 views

What kind of a test is a “consistency check”?

Some or all of the tests I write and run are checks for consistency e.g. assert that if I create a new user account, that the account that was created actually has the same name as the name that was ...
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0answers
48 views

Adding unit tests to brownfield applications [duplicate]

I'm working for a company that has been developing a series of products for years with little to no unit testing in place. They want to move to TDD and unit test new code going forward. However, I'm ...
3
votes
5answers
237 views

Do I need a suite of unit tests for inner business-logic class? Since it's going to replicate the acceptance test suite for 90% [duplicate]

I'm new to TDD and wondering about methodolody. Given: A simple project which implements functionality of, for example, a console calculator. It has the following structure: Fairly simple ...
6
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3answers
450 views

Are “Stocks” a TDD/Unit testing anti pattern?

From Martin Fowler's Mocks Aren't Stubs he states that Stubs provide canned answers to calls made during the test while Mocks objects pre-programmed with expectations which form a specification of the ...
2
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3answers
1k views

Mocking static methods

Having recently returned from a Test Driven Development (TDD) course I had the following thought. While writing unit tests using Mockito we came up against of the problem of mocking static methods. ...
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14answers
5k views

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 ...
5
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4answers
287 views

Building complex algorithms with TDD

I'm trying to adopt TDD in my daily programming practice. I use it at work very effectively, but I'm having trouble with my personal projects where I'm using some complex algorithms. The particular ...