Running Most of the Tests of the CI Build in a Private Build
4. Runs all automated unit tests.David Walker
5. Run component-level integration tests.
Point 4 says we need to run all of the automated unit tests. These tests should be small, isolated, and run quickly so there should be no reason not to run them locally (and, of course, in the CI build).
Point 5 is where we get into the most range as the title of this post suggests. Integration Tests can have some heavy setup overhead and take quite some time to run. Things that take a long time or are painful for a developer to do are likely to be skipped, or glossed over. That is why point 5 says component-level integration tests to segment out a set of automated integration tests that are lightweight in their setup and run time.
Examples are small tests that hit every query or ORM functions to make sure they work properly. Such tests usually require a minimal database that will have just enough data for queries to work. The setup and teardown of the environment should be as quick as possible.
One of the main benefits of the private build is having it share as much build and test code as possible. The more they share the more you benefit from the Top 5 reasons to use a private build.