You could always ignore the TDD portions of the book. Build an e-commerce application with zero tests and I wish you luck. Our company has made good...err...great money for almost two years because of applications that had little to zero test coverage and the developers clients got fed up with the random bugs in the application and wanted a second opinion.
One of the very first things that I encourage potential clients that have existing developers to do is to get the output of... rake stats.
This isn't as uncommon to see as many of us would like.
Code LOC: 9473 Test LOC: 575 Code to Test Ratio: 1:0.1
(real output from a past client that came to us...)
Good luck!
-Robby