Using an SQLite database for testing might come in handy.

Why should we use a database increasing the footprint of a test suite when executing very few queries? 

Even few queries are not prepared the same way depending on the database engine and as a result there is no guarantee of having the same records set returned by SQLite and another database used in production. 

For instance, I've encountered the following issues before:

• Sorting by date might not work out of the box with SQLite (when not using date functions) as there is no date and time Datatype
  
  http://stackoverflow.com/a/1975829/282073
  https://www.sqlite.org/datatype3.html 
  
  
• Having a # character in a query would return an Unrecognized Token error with SQLite, hence could not precede a comment as it could with MySQL
  
  https://www.sqlite.org/lang_comment.html
  https://dev.mysql.com/doc/refman/5.1/en/comments.html