Unit tests are a vital part of emerging code design


Don’t limit yourself. Many people limit themselves to what they think they can do. You can go as far as your mind lets you. What you believe, remember, you can achieve.

Mary Kay Ash

When a developer writes code there is always an aspect of design to it.  Some developers spend more time on initial upfront design others like to start coding straight away.    The design and structure of code will emerge to a more efficient structure during the writing of the code, this process can be helped by writing units to assist the refactoring process.

Designing Code

I like to encourage developers to pause and think about the design of their code before they start writing code.  The benefits from developers thinking before coding

Think before you act

It’s quicker to change a design plan than design and code

This reminds me of the carpenter saying

measure twice and cut once

Thinking = planning

They are stopping to think about the task and creating a design is similar to looking at a map before you set off driving towards a destination.

  • A brief design gives you a plan
  • code designs emerge

You initial design will not be the finished design because designs are high level.  When you focus on individual parts of the design more questions and problems will come into view.

It’s like viewing something from far away, you see some general shapes and details.  The closer you get the more detail you see.

The role of unit testing in code design

Many people believe unit tests are written to catch bugs, it’s true writing unit tests could find some additional bugs you might have missed.

reusable tests for all developers.

It’s true unit testing has many benefits but here are the benefits to code design

Benefits of unit tests to code

  • Refactoring
  • Simpler code design
  • Code Documentation


the main benefit I have experienced with unit tests recently is the ability to refactor my code and run tests against the code to make sure it still works and hasn’t broken anything.

Simpler code design

When code is written to be tested the code design is simplified so testing the code is easier.  It’s easier to test code which does one thing and adhere’s to the single responsibility principle.

Code Documentation

Unit tests provide a working documentation of code.  Allowing other developers to easy see what the code should do by the tests and run/debug the code using the unit tests

This article (which is very good) THE ACTUAL COST OF TESTS – PART I, adds  additional benefits to unit testing

  • Code coverage
  • bugs in tests

The goal of code (design)

The way most developers work is they aim to get the initial code working and aim to tidy the code later.

This approach is driven by two factors

  • working code not matter how ugly can be shipped
  • The developer has proven their logic is sound

Primary requirements of code

  1. The primary requirement of code is deliver the functionality required

long term requirements of code

  1. Readable (expressive names, logically structured)(
  2. Modular/independent code to manage the effects of change (cohesive code, loose coupling)
  3. Reuse
  4. Easy to maintain/debug/enhance the code

The primary and short term goal of code can be achieved with minimal effort in the design of the code.  The code will deliver the required functionality but usually in spaghetti code with these characteristics

  • Big classes and Methods
  • classes\methods doing many things
  • high complexity
  • tight coupling

The above code is what I call Legacy code and developers have given up trying to keep this code manageable because the task of refactoring the project has become to big to contemplate.

An important aspect of refactoring is removing duplicate code, Martin Fowler has a great article on repetition.  Removing duplicate code has numerous benefits such as

  • Create reusable classes/methods
  • Reduces code
  • Better designed code

Unit Tests and refactoring

If you code has unit tests it allows developers to refactor the code with confidence because they can easily test the code still works by running the unit tests.

Unit tests fit in with the way developers write code (get it working first) but without unit tests the refactoring and structuring the code for the long term is  considerable more difficult because the developer would need to manually test the code is working.

Code designs emerge during the coding process, developers see more efficient ways to structure code which usually involves removing duplicate code, writing smaller more efficient code.

Code design can be viewed in similar way to writing a novel.  Novels go through many drafts and revisions whilst the writer removes unneeded sections and poorly written sections.  Some novelists can change the core structure/characters of books during revisions as a byproduct of investing more time focused on the task.

Code design is a similar process because it’s easier to restructure a working code design and improve a current design than it is to create a perfect code design first time.

Problems and efficiencies of code only come into view when a developer moves closer to the problem.

The key points

Without unit tests developers won’t refactor code to deliver the long terms benefits of well designed code.

Code and projects where code is not refactored reach legacy code status very quickly.  The developers who have to manage and work legacy code will take longer and longer to interact with the code (debug/enhance/extend/understand).

The end result is not writing unit tests will cost you more time and developers jobs are less enjoyable


Why CRM Developers should unit test their code

I haven’t written any unit tests for quite some time but I have decided to get back on the testing band wagon.  I will be writing more blog posts on unit testing but I thought I would start with a blog post about the benefits of unit testing.

When you mention unit tests to CRM developers or any developers is a bit of Marmite question.  Some developers love unit tests and some developers dislike writing unit tests and there isn’t much in the middle.

I believe most developers know they are beneficial but because they involve the tricky/boring setting up testing data and if you don’t write tests regularly they can seem difficult to write.

Writing Unit tests will mean you have more code to maintain but the benefits greatly out weight the negatives.

My experiences of unit testing and CRM projects is a lot of CRM practices are not using unit tests (I said this is my experience) or some of them write a few tests but this is usually down to the individual developer rather than a company process.

Why don’t CRM Developers unit test

Here are some of the common reasons/excuses

  • It takes too long
  • I haven’t got time
  • Integration tests will test the code
  • It’s too difficult to test CRM code because of PluginContext
  • The company doesn’t make unit testing compulsory

Benefits of Unit Testing

  1. You already test your code, make the tests reusable and available to others
  2. Tests prove the code works
  3. Unit Tests make you try to break and then fix your code
  4. You can make big changes to the code and test the code still works
  5. The tests can be run every time the code is changed
  6. Testing is not slower
  7. Writing code to be tested creates better code
  8. Testing reduces the number of bugs in the code
  9. Refactoring the code can be done easier and with confidence
  10. It’s great when you get a green light
  11. Unit tests make the code more readable and understandable
  12. Testing before you code helps improve the design of the code
  13. Writing unit tests stops coders block
  14. Less bugs make it out of Development
  15. Bugs unit tested stay fixed
  16. Unit Tests will help you when you have forgotten the business logic
  17. Changing code in one part of the system can break code in another part of the system
  18. You only write test for the required functionality

You already test your code, make the tests reusable and available to others

When a CRM developer writes some code he often tests the code either by creating a console app or by debugging the code (either using the plugin profiler or remote debugging on the server).

I know you are testing your code because you have to test the code before you deploy it.  A lot of CRM developers hope they will find the bugs by integration testing and testing the code from the front end (the CRM web application).

The problem with integration testing is it takes longer to test the code and you have to create the data and test the functionality again every time.

Once you write a unit test to test one part of your functionality you can rerun the test again and again, instead of having to run through the process manually.

Instead of writing a console app or debugging the code, unit tests will enable you have tests you can rerun and more importantly you will have tests other developers can read and run.  If in the future another developer has to fix some code in that area they will have tests to help document the code and will be able to make changes and test the code.

Tests prove the code works

Writing and running unit tests shows the code works and passes the tests.  This depends on you writing effective tests but most of the time you will write tests to test the functionality required.  If you are using Test Driven Development you will write the tests first and then write the code.

Unit Tests make you try to break and then fix your code

When writing unit tests developers will often try to break the code by passing in Null values or unexpected inputs.  These are easy tests to write and help reduce easy/lazy errors from entering the production system.

Often if you are not unit testing the code you don’t think to write defensive code because the main priority is to test the functionality required

You can make big changes to the code and test the code still works

One of the main benefits of writing unit tests is you have created tests to test the functionality.  This means you can change the code and run the tests again to see if it still works.  You can refactor the code with confidence you can test it.

This is an important point for developers who are scared changing some legacy code because they are not sure what code depends on what.

The tests can be run every time the code is changed

Code can get changed lots of time particularly if it’s in a core piece of functionality.  Having tests which can be easily and quickly run every time the code is changed will give you confidence nothing is broken.

When bug fixing often CRM Developers will fix parts of the code they didn’t work on or have little knowledge of.  Unit tests will give the CRM developer confidence their fixes haven’t accidentally broken the code.

Testing is not slower

It would seem logical to think writing units would make the process of writing code longer.  The truth is this isn’t true.  A lot of the time spent on code is fixing bugs after the initial development is done.  Unit testing will help you find more of these bugs up front and reduce the time spent bug fixing.

Writing code to be tested creates better code

When you write code which is easily testable it tends to be better designed and adheres to the single responsibility principle and the code is more modular and reusable.

The developer will also spend more time thinking and designing the code.  Code which is easy to test is easier to maintain and has loose coupling and dependency.

Testing reduces the number of bugs in the code

When a developer writes unit tests they test their code in a more systematic approach and testing various different scenarios.  When CRM Developers manually test their code they usually go follow one or two successful paths through the code.

Refactoring the code can be done easier and with confidence

Refactoring the code can be a lot more confidence when the developer can test the code with unit tests.

It’s great when you get a green light

It’s a great to write a test and then get the green light.  Not only is it a small win it’s great to see how many tests you have running against a piece of code.

Unit tests make the code more readable and understandable

Unit tests

Testing before you code helps improve the design of the code

Writing tests before you have written the code will help the developer think about the design of the code, what they are trying to achieve.

When thinking about writing tests for code the developer will try to simplify the code to make it easier to test.   This process will make the code easier to maintain, debug, extend and understand.

Writing unit tests stops coders block

Writing unit tests stops developers suffering from coders block.  Coders block is when a developers gets overwhelmed by the task of designing the code and doesn’t know where to start.  Writing units tests gets the developer writing code and gives the developer an easy place to start.

The developer can refactor and improve the design of the code later and will be able to test the code works with the unit tests.

Less bugs make it out of Development

CRM Development is complex and the code can contain many bugs.  The aim is to squash as many in the development environment as possible.  Unit testing is one of the tools used to find and fix bugs.

Code reviews and integration testing are the other two main bug detectors.

Unit testing won’t find all the bugs and doesn’t mean you don’t have to do code reviews and integration testing but it will help the CRM developer to find some bugs in his code.

Finding bugs in the development environment is quicker than finding bugs in a production environment, logging the bug, recreating the bug, debugging the code, fixing the bug, retesting and pushing the bug all the way back up towards production.

Bugs unit tested stay fixed

When you fix a bug and unit test the fix, it’s more likely to stay fixed and if it isn’t fixed it can quickly be tested again.

Unit Tests will help you when you have forgotten the business logic

Unit tests are a great way to document the code because you it’s easy to see what the code should be doing by looking at what the test is testing.

Business logic fades (quicker than you think) so a developer has a bug to fix the unit tests will help the developer understand what the code should do.  The CRM developer will be able to quickly test the code with the unit tests.

Changing code in one part of the system can break code in another part of the system

I call this “accidental bugging,” and
it seems to occur a lot near the end of a software project, when developers
are under pressure to fix existing bugs. Sometimes they introduce
new bugs inadvertently as they solve the old ones. Wouldn’t it
be great to know that you broke something within three minutes of
breaking it? We’ll see how that can be done later in this book.

You only write test for the required functionality

You only write unit tests to test for functionality required.  This is a good way to stop developers adding in extra functionality which might be needed in the future.

More reading on why you should unit test

Is Unit Testing worth the effort? 

I Pity The Fool Who Doesn’t Write Unit Tests

Top 12 Reasons to Write Unit Tests

Write Maintainable Unit Tests That Will Save You Time And Tears

CRM 2011 – White Paper – Deploying Microsoft Dynamics CRM 2011 and CRM Online Solutions from Development through Test and Production Environments

Microsoft released an interesting new white paper recently which goes into detail about deploying and testing CRM 2011 in product and test environments.

You can download the white paper here

I wasn’t sure what to expect from the white paper but it was intrigueing because it used good examples and went in detail about how to create test objects (queues, users etc) using code.

I hadn’t really considered importing testing data to such an extent as test business units and user and then assign them to different security roles.

The white paper went into a lot more detailed development techniques than I have seen in previous/similar white papers.

I have always wondered how CRM online companies test their code because unlike on premise CRM solutions they can’t have a test organisation or environment.

This white paper is well worth a read.  Good work