__________ Test is not included in unit testing.

Unit testing verifies the smallest testable part of a program — typically a single function, method, or module — in isolation from the rest of the system. Because the unit is tested on its own, unit-level checks focus on things that can be observed and controlled without the surrounding system: the unit's internal logic paths (structural/white-box coverage), its interface and boundary behaviour, and even its own resource usage or timing under load.

Structural testing exercises the unit's own code paths and is, in fact, the core technique of white-box unit testing, so it is squarely included. Performance and stress checks can also be run at the unit level (timing a function, or feeding it an extreme volume of inputs) to observe the unit's own behaviour, so they too fall within a unit test plan. Security testing is different in kind: it examines vulnerabilities that arise from how components interact — authentication flows, access control across modules, data exposure over an interface — properties that simply do not exist for a single unit tested in isolation. That is why security testing is not part of unit testing; it belongs to integration/system-level testing.

• Performance — measures a unit's own timing/resource use in isolation; testable at unit level, so it is included.

• Stress — feeds a unit extreme/abnormal input volumes to observe its own behaviour; still exercised on the isolated unit, so it is included.

• Structural — the defining white-box technique for unit testing (covers the unit's own internal logic paths); included by definition.

• Question not attempted — not a testing type at all; it does not address unit-testing scope.

Only Security testing requires the integrated system context that a unit test, by design, does not have — so Security is the test that is not included in unit testing.