The tests that a system can be subjected to can basically be broken down into two groups: White Box Tests, and Black Box Tests.

White Box (Structural) Tests
White Box Tests are tests that require knowledge, and access, to the code itself, and therefore are performed by the developers. These types of tests include Unit Tests (eg: NUnit), Code Coverage (see NCover, PartCover.), etc.
White Box Tests are generally considered Structure Tests, as they test the actual system internals.

Black Box (Behavioral) Tests
Black Box Tests on the other hand, do not require knowledge or access to the system's code, and can therefore be performed by Quality Assurance Test Engineers, who only have access to the system in a compiled state. The most common tests they will run are a basic Smoke Test, as well as Browser Tests, Spelling Tests , Accessibility Tests, Load Tests, Response Time Tests, etc.

Real World
There are a lot of tests that your software can be put through -- in theory.
In the real world, testing is limited to a very small subset of them (eg: browser, accessibility (for gov), stress, spelling, etc.) before the system is rolled out.

The tests that a system can be subjected to can basically be broken down into two groups: White Box Tests, and Black Box Tests.

White Box (Structural) Tests
White Box Tests are tests that require knowledge, and access, to the code itself, and therefore are performed by the developers. These types of tests include Unit Tests (eg: NUnit), Code Coverage (see NCover, PartCover.), etc.
White Box Tests are generally considered Structure Tests, as they test the actual system internals.

Black Box (Behavioral) Tests
Black Box Tests on the other hand, do not require knowledge or access to the system's code, and can therefore be performed by Quality Assurance Test Engineers, who only have access to the system in a compiled state. The most common tests they will run are a basic Smoke Test, as well as Browser Tests, Spelling Tests , Accessibility Tests, Load Tests, Response Time Tests, etc.

Real World
There are a lot of tests that your software can be put through -- in theory.
In the real world, testing is limited to a very small subset of them (eg: browser, accessibility (for gov), stress, spelling, etc.) before the system is rolled out.