Python Testing without sql connection

• I am using sql to pull in values from 'lookup' table. I will use cursor and fetchall and then loop through values and place them into dictionary. I do not see reason to keep querying database(open conn, query, close conn) for every lookup performed when a dictionary of subset of data should suffice. Is this 'standard' practice to use dictionary in-lieu of table ?
• Is there a way to test this with different sets of values without connecting to database? Some framework or some pattern? Not sure what to investigate.