Even when using TDD, there comes a time when the inevitable occurs that you need to run the application and see how the changes you made effect the application in whole.
In the application I work on, it is very large with a environment that is large and brittle. When I need to run the application, I dread it. About 25% of the time, you need to overcome other problems to get to the meat of your testing. Some of these problems can be overcome by getting a newer version of the source code. Some of these problems can be overcome by getting newer binaries of "second party" DLLs we use. Some problems are within the database or web servers, so it get outside of your control.
This is what I would like to dub "Marco Polo Testing".
Marco Polo Testing - phrase - The act of executing a large piece of software to test a single aspect of it. Upon trying to arrive at the single aspect, you encounter many different unexpected situations. None of these situations were predictable, you have little to no control over any of them. By the time you arrive at the place in the software you wanted to test, you've forgotten why you were going there.
From wikipedia, Exploration
Exploration is the act of searching or traveling for the purpose of discovery, e.g. of unknown regions, including space (space exploration), for oil, gas, coal, ores, caves, water (Mineral exploration or prospecting), or information.
The term can also be used to describe the first incursions of peoples from one culture into the geographical and cultural environment of others. Although exploration has existed as long as human beings, its peak is seen as being during the Age of Discovery when European navigators travelled around the world discovering new worlds and cultures.
In scientific research, exploration is one of three purposes of research (the other two being description and explanation). Exploration is the attempt to develop an initial, rough understanding of some phenomenon.
