# \[ANN\] Merb Mind Maps - a tutorial on RSpec, GraphViz & a little Merb

**URL:** <https://www.ruby-forum.com/t/ann-merb-mind-maps-a-tutorial-on-rspec-graphviz-a-little-merb/160443>\
**Category:** Ruby\
**Created:** [February 16, 2009, 1:30pm UTC](https://www.ruby-forum.com/t/ann-merb-mind-maps-a-tutorial-on-rspec-graphviz-a-little-merb/160443 "2009-02-16T13:30:24Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Phlip](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/ed8c4c/32.png) [@Phlip](https://www.ruby-forum.com/u/Phlip)\
**Post date:** [February 16, 2009, 1:30pm UTC](https://www.ruby-forum.com/t/ann-merb-mind-maps-a-tutorial-on-rspec-graphviz-a-little-merb/160443/1 "2009-02-16T13:30:24Z")

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Netizens:

Crispin & Gregory’s new book, /Agile Testing: A Practical Guide for  
Testers and  
Agile Teams/, has a kewt “mind map” at the start of each chapter. It  
inspired me  
to find a way to use the “tag cloud” on a blog to draw a mind map of the  
posts,  
linked by their tags in common.

The result is this little project:

[Radar – O’Reilly](http://broadcast.oreilly.com/2009/02/merb-mind-maps.html)

It showcases…

- graph theory - including Minimum Spanning Tree
- GraphViz - to typeset the mind maps
- Merb - a Rails-style website platform
- Ruby - that annoying language that won’t go away
- RSpec - a Behavior Driven Development system
- transparent PNG files with ImageMagick drop-shadows
- assert{ 2.0 } - an assertion that reflects its expressions
- assert{ xpath } - the latest version of my assert\_xpath system
- TDD for algorithms & graph theory!
- fixture-dependencies - a Rails fixture clone with more features
- GraphvizR - a lite Ruby gem that wraps GraphViz dot notation
- and even a tiny bit of HAML!

The algorithm itself depends on none of those things, so any blog could  
use the  
algorithm to present the mind-maps that are already latent within it!