Home / Posts tagged "Test Driven Development"

Clean Code: Test data preparation or what test data builders are good for

Today I read this blog post about how to simplify test data preparation.

The author of the blog post states that setting up test data for tests is sometimes difficult and bloats up the test code, resulting in bad readability and maintainability. I completely agree with that.

The author continues by solving this problem by loading the test data from a file and using it in the test. That minimizes the code needed to set-up the test data, but results in a disconnect between the test and the data or example used for it. Leaving us with an obscure unit test.

We solve this problem differently.

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FakeItEasy and Windows Store Apps are becoming friends

Probably you already know it: The new Windows Store App class libraries prevent proxy generating using frameworks like Castle.Core because System.Reflection.Emit namespace is missing in the limited framework they’re using.

But we still want to do TDD and therefore we need a nice mocking framework, like FakeItEasy, don’t we?

In this blog post I will show you the best way I came up with to develop Windows Store App compatible code with TDD.
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Create your own hamcrest matcher

If you are familiar with hamcrest and JUnit the time will come when you have
the need to create your own matchers.
Creating your own matcher can be as simple as useful. One reason for
creating your own matcher could be that your object is not a default object
like a String or a Collection. And if you would like to get a more readable
version of the assert for the next developer who has to read your
test. Let’s make an example. If you have an object with two methods;
getName” and “getNumber” and you would like to check whether the resulting object
has the correct values.
In my opinion the best way to verify this is to create two matchers and
combine them. Before we can combine these two matchers let’s see how to
create them. Continue reading

No more development, TDD begins with MoreUnit

Do you program or do you already TDD? 🙂
If you prefer to do TDD you will love the eclipse plug-in called MoreUnit. It is as simple as powerful. All it does is executing tests from corresponding productive class and makes it very simple to change between them.
Just press Ctrl-J (like Jump) to jump from test to implementing class and the other way. Or press Ctrl-R (like Run) to run the test regardless if you are in the test or the implementation class. Continue reading

Mockito – ArgumentMatcher vs ArgumentCaptor

Since a few weeks the new mockito release candidate is available. So I think it is the right time to place a new post. Here I will show the differences between ArgumentMatcher and ArgumentCaptor. Most developer will first see the ArgumentMatcher and use it. What can be done with ArgumentCaptor is often not seen. With the sample I will show that an ArgumentMatcher should not be used to fetch arguments. For this work there is the ArgumentCaptor. The Matcher should really be used to check if an argument matches or not.
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Refactoring in Test Driven Development

cross-post from www.bbv.ch/blog

In the last two years I gave over a dozen courses and presentations about test driven development (TDD). One question, I get asked almost every time, is how to refactor code while keeping up the TDD rules:

  • write only production code if there is a failing test requesting it
  • have no more that one failing test at once

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Clean Code and Clean TDD Cheat Sheets

Updated: new version here!

I have compiled two cheat sheets about clean code (the ones mentioned in my post about Code Quality!).

The first covers clean code – code that is easy readable and keeps changeable. The second is about Test Driven Development. Both cheat sheets list principles, patterns, practices and smells.

You can download them here – Clean Code Cheat Sheet V1.3, Clean TDD Cheat Sheet V1.2.

Take a look!

I’d like to read your feedback in the comments section…

Clean Code

(just an unreadable preview 🙂   – click on link in text above)

Speaking at BASTA! in Mainz (Germany) on September 21st 2010

I’m going to speak about code quality (see my short version of the presentation) at the conference BASTA!

BASTA! is mainly focused on .NET technology and gives you the opportunity to see and speak with a wide range of technology experts.

If you have any feedback of what you are missing in my short presentation, please write a comment here or on the post with the presentation. The short version takes about 30 minutes and my speak at BASTA! is scheduled for 1 hour and 15 minutes.  I will mainly show real life examples of the theory shown in the short version. But if you want to here something specific, ask for it 🙂

I’ll probably will publish the long version on this blog, too – for all of you not joining the conference.

So long…

Create mocks with mockito

This is a small summarization what the differences are between the different variations creating mocks with mockito.

Null values (default)

Per default, after creating a mock, every method will return null. Just create your mock with:

Sample sample = Mockito.mock(ISample.class);

I think, this is very useful and straight forward. (And based by mockito developers idea, to create very fast a mock for testing). Sometimes it is very difficult to determine an error which was produced through such a null value. For this case it is very practicable to tell mockito, returning SmartNullValues.

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