When django runs tests it creates a new database from scratch. This isolates test data from your production or development environment. Without proper configuration, this database will lack the PostGIS functions needed to run those tests and reproduce Madrona’s data model.
There are two different approaches to getting PostGIS working within these newly created databases.
If altering the properties of every newly created database is undesirable, GeoDjango has made the process of spatially-enabling just the test databases easier. See Testing GeoDjango Apps.
Another option is to spatially-enable all databases created on your system. By default new databases are created from a template called template1. Any functions or data added to this template will appear in the new databases, whether they are created by the django test framework, another tool, or the postgres shell itself.
The PostGIS documentation has a section on spatially-enabling a database. Simply follow those instructions, installing spatial functions and the reference system into template1.