Types of code

Legacy code

One of the definitions - The code without test cases.

Greenfield code

In many disciplines agreenfield projectis one that lacks constraints imposed by prior work. The analogy is to that of construction on greenfield land where there is no need to work within the constraints of existing buildings or infrastructure. In software development, a greenfield project could be one of developing a system for a totally new environment, without concern for integrating with other systems, especially not legacy systems. Such projects are deemed as higher risk, as they are often for new infrastructure, new customers, and even new owners. For this reason, agile software development is often deemed the best approach, as it proposes how to handle those risks by developing small slices of complete functionality and getting them in the hands of customers (internal or external) quickly for immediate feedback.

Brownfield code

Those facilities which are modified/upgraded are called brownfield land projects (often the pre-existing site/facilities are contaminated/polluted.) Brownfield development is a term commonly used in the IT industry to describe problem spaces needing the development and deployment of new software systems in the immediate presence of existing (legacy) software applications/systems. This implies that any new software architecture must take into account and coexist with live software already in situ.