Test Driven Development in .NET

Test-driven development is a development pattern which is
characterized by the use of pre-written test cases which are
continuously validated via an iterative, incremental development
process.

The basic process is:

1. Write the test.
2. Write the code which is tested by the test from step 1.
3. Validate that the new test and all previously implemented tests
run successfully.

The process is repeated for each test until the code is fully implemented.

Benefits of test-driven development include:

* Forces simplicity in the code by breaking down complex tasks
into individual subtasks.
* Ensures that the developer understands the intent of the code
before writing it.
* Allows defects to be detected early in the development lifecycle.
* Prevents regression by identifying breaking changes prior to
release of new versions of the code.

It is important for buyers of software to understand that a solution
developed with automated testing (whether or not it is a result of
test-driven development or build-then-test development) will have a
higher up-front cost. However, automated testing can be expected to
pay for itself over the total software asset lifecycle through reduced
occurrence of bugs and the limiting of regression.