A Test Cut element is a stereotyped Object element, used internal to Enterprise Architect for defining Test Sets using the Testpoint code testing facilities.
A task, such as 'Print', might involve operations on different Classes. In order to create a 'Print' test, you would want to include only the 'Print' operations of these Classes and exclude any other operations.
A Test Cut enables you to capture only the operations that represent the behavior (in this case, 'Print') defined for a single Class. You might then place the Test Cut from each of several Classes into a single task as a Test Set.
When you drag a Test Cut element onto a Test Domain diagram, you create a Dependency relationship with the required Class element. As a result, when you select the Test Cut element on the Testpoints window, the operations of the Class are listed in the window, each with a checkbox. You then select the checkbox against each Class operation to include in the Test Cut.