Creating Test Case from Requirement
Creating a Test Case directly from a related Requirement is also easy. Just open a Requirement issue and click the "Create Test Case" button found in the "Test Cases" section.
[Screenshot - UG0023_Test_Case_issue_Create_From_Requirement]
As the Test Case is created from the Requirement, relations between Test Case and Requirement will be established automatically. You need not associate the Requirement manually for the Test Case you are creating.