Refactoring legacy code driven by tests (I)

We'll work in the first of Luca Minudel's refactoring legacy code exercises.
It's a very focused exercise two practice several in which we'll have to detect and refactor some violations of the SOLID principles in the original code. This code is very untestable, so in order to test it, we'll first have to detect where the possible seams are and make the code testable by applying some dependency-breaking techniques from Michael Feather's Working Effectively with Legacy Code Book:

• Extract and Override Call
• Parameterize Constructor
• Extract Interface