Lettuce is a BDD tool written in python, 100% based on cucumber.

There are two reasons for the name:

• Lettuce is a green vegetable, just like cucumber the idea is that your tests must be always green.
• Letuce is the name of a brazillian band that I pretty much like

Hands on!

There are links to lettuce’s official documentation at the end of this post, but there is a sneak peak:

Features are described in files with .feature extension and must be, by defaul within your project, in a folder called “features“.

Features are described like this:

In order to define steps all you need to do is write a new python file wihin features folder, Lettuce will import them all, recursively.

Example:

(the full example is available here aqui)

Motivation

Since I started with TDD in Python I had many experiences, I’ve tested many mock mock libraries and test techniques.
In web projects I’ve used Pyccuracy, so that I could both describe behaviour of the application and make automated acceptance tests.

Althrough, I had a chance to try Cucumber with Django here at globo.com, and the result was: I fell in love with it, and had incredibly productive features, such as step tables which allows drawing a ascii table and map it into a list of hashes, and the scenario outlines.

From there I had THE inspiration: to implement a tool that works exactly like Cucumber, but in python.

Why ?

Python programmers it’s easier and frictionless to use libraries written in Python. I personally avoid mixing programming languages in a single project, some technologies can suit perfectly in the project, no matter in what language, but if there is a Python option, I will give it a go.

Cucumber IMHO one lib to make ruby even more “sexy”
Build a robust application, well tested required patience, what about turn it into fun ! ?
It’s easier to package python modules for debian/ubuntu.

Besides, even considering the fact that  Cucumber already supports, would be more interesting to user pure python within step definitions.
Supposing that a web application will be written with Django and Cucumber, would be very useful to manipulate models within step definitions. However turning it possible, would need efforts to run rubypython, which the latest release dates october 2009.

Examples of similar libraries between python and ruby

Web framework:

ruby: rails
python: django

Micro web framework:

ruby: sinatra
python: cherrypy

Automated deploy:

ruby: capistrano
python: fabric

Behaviour-driven development:

ruby: cucumber
python: lettuce ?! (maybe ?! Who knows ?!  )

More on lettuce

Documentation

Available at http://lettuce.it covers all supported features until now.

Contribute!

I’ll appreciate all kinds of feedback, to do so we have some channels:

• GitHub repository
• Junte-se à lettuce users mailing list
• bugtracker !

Lettuce is under GNU GPL 3+ and have a long way until get robust, and any kind of help is welcome: patches, documentation, language support and so on!

Grab it, and happy hacking

Trata-se de uma ferramenta de BDD 100% baseada no Cucumber.

O nome teve duas motivações:

• Lettuce (Alface) é um vegetal verde, assim como Cucumber (Pepino), a idéia é que os testes sempre estejam verdes
• Letuce é também o nome de uma banda à qual tenho muita admiração.

Mãos ao código

Deixei links para a documentação no fim deste post, mas aqui vai uma prévia:

Funcionalidades são descritas em arquivos com a extensão .feature, e devem ficar por padrão, dentro do seu projeto, chamada features

Por sua vez, features são descritas assim:

Para implementar as steps, basta criar um arquivo python qualquer dentro da pasta features o Lettuce importará todos eles recursivamente.
Exemplo:

(baixe o exemplo completo aqui)

Motivação

Desde que comecei a praticar TDD em Python tive várias experiências, testei várias bibliotecas de mock e técnicas de teste.
Em projetos de aplicações web usei o Pyccuracy, assim podia descrever o comportamento da aplicação ao mesmo tempo que fazia testes automatizados da interface.

No entanto, tive a chance de testar o  Cucumber num projeto Django aqui na globo.com, me apaixonei por funcionalidades incrivelmente produtivas, como step tables que permite desenhar uma tabela com caracteres, e mapear como lista de hashes, bem como scenario outlines.

Daí veio a grande inspiração: implementar uma ferramenta como o Cucumber, mas em python puro.

Por que?
Para programadores python, é mais cômodo usar bibliotecas em python puro. Eu pessoalmente evito misturar linguagens, a não ser que a melhor solução seja realmente em outra linguagem.

Cucumber é, na minha opinião, uma lib que torna ruby ainda mais sexy
Criar uma aplicação robusta, bem testada requer paciência, que tal tornar isso mais divertido ?
É mais fácil empacotar módulos python para debian/ubuntu

Além disso, apesar de Cucumber dar suporte a Python, seria interessante usar python puro dentro das step definitions.
Supondo o desenvolvimento de uma aplicação Django com cucumber, seria útil manipular os models dentro de step definitions. Entretanto, para isso acontecer, é necessário usar algo como rubypython, cuja última release data outubro de 2009.

Exemplos de bibliotecas similares/equivalentes entre python e ruby

Framework web:

ruby: rails
python: django

Micro-framework web:

ruby: sinatra
python: cherrypy

Deploy automatizado:

ruby: capistrano
python: fabric

Behaviour-driven development:

ruby: cucumber
python: lettuce ?! (quem sabe  )

Direto ao assunto!

Hoje estou liberando oficialmente a primeira release candidate do Lettuce, que atualmente possui as seguintes features:

• Hooks pre/pós execução de:
  • Toda a suíte de testes
  • Cada feature
  • Cada scenario
  • Cada step
• Contexto global: world
• Scenario outlines
• Step tables
• Nomes e formato de arquivo de features compatível com cucumber
• Output colorido
• Output sem cor

Mas… O que falta para fechar a primeira release oficial? Além de ter feedback sobre possíveis bugs das features já implementadas para melhorá-las, a intenção é que a primeira release também tenha as seguintes funcionalidades:

• Suporte a features escritas em português
• Tratamento de KeyboardInterruption
• Documentação completa

Documentação

Não poderia faltar, mas ainda está sendo escrita.
De qualquer forma, já possui o básico para colocar o um novo projeto funcionando. E se você já conhece o Cucumber, não terá dificuldades.

Acesse a documentação aqui

Ou melhor ainda, vá direto ao “quick start”

Contribua!

Estou sedento por feedbacks (negativos e positivos), sendo assim:

• Obtenha o código no repositório git
• Junte-se à lista de discussão de usuários do lettuce
• Acesse o bugtracker !

Por fim, o lettuce está sob GNU GPL 3+ e ainda tem um longo caminho pela frente. Toda forma de ajuda é bem vinda, seja com patches, documentação, suporte para outros idiomas, etc.

Happy hacking

Couleur indeed turns very easy to handle shell colors in python.

In action

Couleur creates colored output dinamically, so that you can mix colors and modifiers at will:

And even use “static” output, let’s simulate the output of a “git clone”:

Installation

Full Documentation

Available here

Contributing

Fork me on github, write tests, write code, make it pass, send a pull request

The hack parties had no specific goal, but a main idea: Hack some free software, and share the knowledge.

Many of us, but specifically Lincoln and I, used to create new projects in every hack party,but only a handful of those were actually released. It was often matter for jokes like: “Oh, you are up to raise the “too many projects” exception”.

I have two words for that fact: “not agile”.

Our projects were often POCs, and we had no culture of TDD, short releases and so on.

But since I started to work at Globo.com, I learned so much about agile, specially Scrum. And some months ago I’ve just accomplished what I call as “agile feeling”.

I mean, it’s a feeling that I can deliver software with quality in a short period of time.

But how ?

The idea is quite simple, you just have to follow some principles:

Think simple

This basically means focusing at the problem at hand, never trying to solve future problems you don’t have. Most of the time the problems your foresaw will never happen, yet you spent a lot of time preparing for them.

Test before programming

Write tests for small parts of your software, they will be very modular, and you will get a trust-able software, and I can assure you that you will be 100% able to embrace the changes.

Release fully functional versions, with simple features

As human beings, we want to embrace all possibilities and solve all possible problems at once.

But this is not agile at all. Talk to your client, be pragmatic, he will like to listen the truth: “You can not ship a full-featured final version of software within the term. But you can totally ship a primary version, fully functional, with all the basic needs of the client. Keep improving the software in next releases”

I tried to summarize those thoughts, but I need blog posts for each one.

Applying those thoughts to personal projects

As I said, I have unfinished projects, and they are still unfinished, mostly because were started with a non-agile approach, and I can’t get interested to finish them.

But there are a few projects I worked in, and others I am the creator. For instance:

• Dead Parrot, a pythonic RESTFul framework django-based. Is on release 0.1-hellopolly, being used within some globo.com projects.
• Ma-Chérie, a simple filesystem-based web application to navigate through pictures. Current release: 0.1
• Sponge, a tiny web framework built on top of CherryPy and used Genshi as default template language. Sponge is the base of Ma-Chérie. Current release: 0.1
• Pyccuracy, s BDD acceptance testing tool. Heynemann started that project, as a comitter, I worked in the biggest refactoring. Current release 1.0.3-viagra
• Sleepy, is a crude, slow and rough template language, 100% based in regular expressions (which mades sleepy so slow). Actually I do not plan release it by now,  I am just having some proofs of concept of how possible is to write a template language 100% regex based, just with TDD.

All projects above, except Sleepy, were released as well, all them were developed with TDD and have  a good code coverage.

But the big deal is that, actually they will never get finished, for a simple reason. They will be in continuous development and continuous released as well.

By the way, if you want to contribute, just go to my github profile and check them out.

Once I am a Django web developer, one of my first actions were to create a django deployment setup, good and flexible enough. The time passed on and have been got new experiences, and the best desision, i think, was to create a new python sandbox, i mean, a customized python environment.

How is it possible ?

Simple! Just compiling python from scratch, with a fake root path (a prefix)

Anyway, the deployment process involves more variables, like setting both htaccess and dispatch files for each project, installing some basic modules such PIL and MySQL and so on…

So, i ever wanted to create a super duper script to do all that “dirty” work. And i did it last weekend!

I were working ia a freelance job and decided to create a subdomain to host test instance of them.

A new sandbox, ready to make my tests to create the super script.

So folks, i present you the brand new: django_dreamhost.sh

It’s composed by 4 files:

• django_dreamhost.sh itself
• djangify.template – a template with will become a script to setup new projects (htaccess and dipatch files, for instance)
• htaccess.template – a template that will become the .htaccess of each project of yours
• dispatch.template – will become the dispatch.fcgi for your projects as well

“But do i need to download all them ?”, of course NO!

You just download the main script, and he will do all do hard work!

“I wanna contribute, modify or do anything with that script, can I ?”, of course yes! All parts of the script are GPLv2 +

You can also always get the development version through git repository:

git clone http://git.nacaolivre.org/django_dreamhost

Don’t want to get all code, just the script ?

Download it at: http://gnu.gabrielfalcao.com/django_dreamhost/django_dreamhost.sh

What does that script do ?

He will do the following steps:

1. Download Python, Django, Python-setuptools, Python-fastcgi to a directory called downloads
2. Extract all
3. Create a local root at $HOME/.myroot and the subdirs etc and usr
4. Set the new bin path to you global path through bashrc and bash_profile
5. Compile and install python to the new prefix: $HOME/.myroot/usr
6. Install Django, rename django-admin.py to django-admin
7. Setup your bash-completion to support django scripts
8. Install the python modules above with the new python
9. Install PIL and MYSQL modules through easy_install (setuptools)
10. Download the template scripts to $HOME/projects/script_templates
11. Replace the custom tags in templates
12. Move the djangify.template to the new bin PATH: $HOME/usr/bin and give it execution permission

I thinks it’s all.

I currently use Fabric to help on deployment, and i have a quite smart basic setup for it to work with this dreamhost django environment, but it will be approached in the next blog post

See you, folks!