When is a Test not a Unit-test?

Question

I am looking for rules like:

A test is not a unit-test if:

• it communicates with a database
• it cannot run in parallel with other tests

Answer 1

A test is not an Unit Test when:

• it tests more than one thing at once (i.e. it tests how two things work together) - then it is an integration test

Checklist for good unit tests:

• they are automated
• they are repeatable
• they are easy to implement
• they remain for future use, once written
• they can be run by anyone
• they can be run by the push of a button
• they run quickly

Some more best practices (in no particular order of importance):

• tests should be separated from integration tests (which are slower), so that they can be run fast as frequently as possible
• they should not comprise too much logic (preferably, no control structures)
• every test should test only one thing (thus, they should contain only one assert)
• the expected values used in assertions should be hard-coded and not computed at test run-time
• external dependencies (filesystem, time, memory etc.) should be replaced by stubs
• test should recreate the initial state at test shutdown
• in assertions, it is better to use a "contains..." policy, rather than "is strictly equal..." policy (i.e. we expect certain values in a collection, certain characters in a string etc.)

This is part of the knowledge I have extracted from Roy Osherove's book - The Art of Unit Testing