Prevents further assertions, types, styles, plugins, and themes from being added to the instance.
Once frozen, the
use methods will
throw an exception.
Cloning a frozen instance is allowed, and clones will not be frozen initially.
Creating a child is also possible, but the child won't support
exportStyle because the parent
expect is frozen. This means that some
plugins cannot be installed into the child. To get around that, create a clone first.
The plan is to make the top-level
expect (the main export of
frozen as of Unexpected 11. The idea behind that is to help prevent multiple files in a
test suite from affecting each other by forcing each file to create its own isolated clone.