Found a solution that works for me:

package TestModules;

use MyApp::Schema;

MyApp::Schema->connection(
  'dbi:SQLite:dbname=:memory:',
  '',
  ''
);
MyApp::Schema->load_namespaces;
MyApp::Schema->deploy;

# set data
MyApp::Schema->resultset('TestModule')->create({
    id => 1,
    name => 'Test',
  });
1;
[download]

So, just load this module before tests (on using modules that query DBIx::Class models) and it works.