If you have developed tests that you would like to share with other instructors, you can export the tests and question pools by themselves, without any other course content.
If you also check both the Grade Center Columns and Settings and the Content Area where they are posted for students, it will also also export links to your tests, along with the deployment settings that you used (dates available, date due, time allowed, etc).
However, it also copies all the other files in that Content Area, as well as all your gradebook columns, reducing your ability to share only the tests and question pools. If you have added a content area to the course menu specifically for your tests, then that will prevent any additional content from being copied, but may still include other Grade Center columns.
Click Submit - Ted should confirm that it has started creating the archive: 

You can then share that .zip file with anyone who wants to use the tests, who can then import it into their class:
It will send an email confirming the tests have been imported.
The instructor can then post the tests to the Content Areas to assign them to students. You may prefer to add a content area to the course menu called "Tests" or "Assessments", and post the tests there.
The new class also receives all the pools of questions, allowing the instructor to delete the existing tests and create new ones using your question pools.
When you create a test and are editing the test's questions, next to the Create Question menu is a Reuse Questionmenu:
Each one of these options will let you select questions from a question pool (or previous tests) in your class to add to the test.
For both the Question Set and the Random Block, you can then decide how many of the questions should be seen by each student, and how many points should be awarded per question. Displaying, for example, 5 out of 10 questions for each student can ensure that no two students can share answers with one another, or allow a student to take the test multiple times and see new questions each time.