How could you generate test data with no input data?

CTS,

How do you debug and test your SAS programs? What can you learn from the SAS log when debugging? How do you test for missing values? How would you create multiple observations from a single observation? What are some good SAS programming practices for processing very large data sets? Briefly describe 5 ways to do a "table lookup" in SAS. Why is SAS considered self-documenting? Are you sensitive to code walk-throughs, peer review, or QC review? What other SAS features do you use for error trapping and data validation? How does SAS handle missing values in: assignment statements, functions, a merge, an update, sort order, formats, PROCs?