Archive for November, 2009

Motivation is a …

Bitch. Well sometimes at least.


Right I just feel like: “Blog? Meh…”


I’ll be back when I have something interesting to say (If I ever do have something interesting to say :))


Categories: Uncategorized

What license to choose?

Crap… I have hit a big roadblock when I’m on my way to release my first open source project. I have to choose a license. I thought it would be fairly easy but after talking to two of my colleagues it turned out it wasn’t as easy as I thought.

I had for a time taken GPL as some kind of standard because many of the tools I use are under GPL license. The problem with GPL was however that it “rubs off” on other software and since my application is going to have plugins it wouldn’t work. The reason is that I don’t want to force the user to release the source code for the plugins, I want authors to be able to sell them if they like or to provide a plugin as part of their product. I was thinking about LGPL but I don’t understand it all.

This made me look at a BSD license but then I found out that any company could potentially just fork my code and release it under another name and probably change the license as well. Needless to say I didn’t like that… it may work for people who don’t care about companies swooping in and reaping the benefit of people who worked hard on an really good application and then just sell it.

What about Mozilla license then? Well I’m currently looking at it and it looks good… but there are two problems 1) it is long and 2) I don’t understand it all. This is one of the biggest benefit of BSD license which I understand but don’t fully like for this particular application. Honestly these licences are crap… I have officially started to hate lawyers and law stuff because of this… Why can’t they just write in plain English (or what ever language they prefer). What does it mean to sub license? Does it mean you can license your modification under a stricter license? I’m all too confused by this.

MIT seemed like a choice (during another discussion) until I realized it was just BSD.

This is what I want:

  • I have a framework which is completely open. If someone changes anything in that framework then they can redistribute that change but they can not close the source and they must notify me (“the author”). They can not sell any part of the framework and I have the right to add any change that they put into their branch of the code without limitations. They can not say they made it as initial author, they can say they forked it. They can not remove the initial author’s name from the source code but they can add their own.
  • In the framework that have plugins. Plugins are clearly specified through an API. Everything on the framework side is the framework (duh) and everything else that the framework calls is the plugin (again; duh). If a plugin is developed then the license of that plugin can be what ever the author wants except for a license that would somehow possible affect either the framework or other plugins.
  • I reserve the right to be wrong and can change anything I want without notice and I am not responsible for anything at all.

Bah… what to choose? This was harder then I thought.

I just realised, I’m presenting att tomorrow… they MUST be able to answer this kind of stuff. Follow-up post tomorrow!


Categories: Software Tags:

TDD, time wasting and Psuedo-Tests

2009/11/04 5 comments

I’m probably going to be shot, stabbed, burned drowned and buried because I’m writing this but I hope that I reach out to enough people before I go out!

My friends, watch out! TDD can be a really huge timewaster.

When did you know exactly how you expected your application/component to behave? Probably you didn’t until you tried a few things out, then sketched on some paper then thought some more then tried some other stuff again and then got back to paper etc. After that you had a perhaps clearer idea of what it was that you want to create. This is prototyping and it should be the first stage in any new/enhanced application. Once this has been done and you know the properties of your system then you can commence TDD.

If you didn’t do prototyping and you naively started writing your unit-tests then you have just wasted your time. I really don’t understand how people can argue that they should write tests first before they implement anything. If you write a test and expect it to mysteriously define your application then you are better off just using water-fall. I don’t feel very “agile” when I’m sitting there writing unit tests for something I will develop just to realize that I need to re-write the tests every 10 minutes. ALL the tests that I write before I write code I need to constantly rewrite… This is a black hole for time.

Instead I propose psuedo-tests.

Before I continue some people are probably going to argue that I “didn’t do it right” or that “it works for me you must be doing something wrong” well I don’t really care because you probably wasted your time and you didn’t know about it. I tried the whole lot and it is such an annoying thing that I don’t understand how it has become so popular. TDD should have a big IF in front of it like this: “IF you are going to do TDD, then make sure that you KNOW what it is you are going to develop”.

So what are psuedo-tests?

A psuedo-test is a test that doesn’t test anything it is just used to conceptually affect the design of your code. It is like psuedo-code but instead describes how the tests will run (instead of how your algorithm or code will run). This has the following benefit on your development

  1. Psuedo-code is _very_ easy to change. You don’t have to care about the actual interfaces or compilation or running or changing details everytime your code change.
  2. Your code takes testing into consideration. Things like get/set functions and various introspection function are taken into account, you seldom have to add these later. In Erlang e.g. it is usual to have a start/0 function instead of start_link/0 for testing purposes.
  3. The tests become simpler and smaller and easier to understand. Why? Well because you don’t have to rewrite your tests 600 times, you rewrite less often. Many people forget that tests are code as well and re-writing something and building on top of things in a very fast pace creates bulky code.
  4. If you write enough psuedo-tests then the step to property-based testing is not far (using tools like QuickCheck etc).

Example: We want to create a supervisor, then one test could be:

test_sup() ->
  Start supervisor
  Start a child under the supervisor
  Check that the supervisor has 1 child
  Check that the child of that supervisor is alive
  Kill the child
  Check that the supervisor has 1 child
  Check that the child of that supervisor is alive
  Stop supervisor

Then during implementation you realize that it would be a good idea to kill the children if the supervisor was stopped so instead of implementing it in your test code immediately you simply update your psuedo-test first adding

test_sup() ->
  Stop supervisor
  Check that the child is dead

This is much faster and you don’t have to care about implementation details… you can get on with your coding. The test is your specification and your guide without wasting your time and as you can see… this isn’t very far from a property if you define it well enough. Then just abstract this test to handle N children and you are good to go for a property test. When you have something substantial to test then implement your tests and run it!

NOTE however:
I am NOT saying that you shouldn’t test! That is not at all what I’m saying… you should always properly test your code. I’m just saying don’t spend all your time writing silly tests just because you are doing “TDD” or whatever… have the tests make sense! Test something substantial that make sense!

Just a thought… Now I’m going to bed…


Categories: Erlang, Philosophy Tags: