But, I feel like if a team really did have 100% code coverage of their unit tests, there'd be a couple of problems.
Run that unit test as part of a standard build from that moment on.
It has first class support for unit tests and contracts.
In Java, to execute a unit test from the command line, a class can have methods like the following.
A final is technically just a greater form of a "unit test".
When software is developed using a test-driven approach, the unit test may take the place of formal design.
These unit tests are also constantly run as a form of regression test.
Therefore, extra work may be necessary for unit tests.
There are fewer of them, and they must be run less often than the unit tests.
As a result, unit tests find problems early in the development cycle.