SimpleTest not creating tables

I am using the SimpleTest module version 6.x-2.8 with Drupal 6.13. I wrote a custom module, for which I wrote some tests. However, SimpleTest doesn't seem to be creating a copy of the table associated with my custom module, because I get an exception message for every time I try to insert something into the table or query it in the SimpleTest.

All insert queries result into something like this in the SimpleTest results page:
Table 'db_name.simpletest692319new_table' doesn't exist query: INSERT INTO simpletest692319new_table(...)

hook_schema() defined in my .install file for the module. Does anyone know if there's anything else that SimpleTest needs in order to recognize my table and create the copy of it?