Highlighted by Stanciu Valentin
From TDD using Quick & Nimble by Radim Halfar
Describe exactly describes what component you are testing.
A Vehicle.
Context describes the purpose of the test or the current state of an object.
After being properly initialized as a Car. (You can and definitely should create tests that will test the inappropriate state of an object.)
It describes the expected result of the test. This is the exact test case.
Should be driveable. (Any expectations can be defined)