Integration testing complex transactions in grails can be tricky due to the default behavior of wrapping integration tests in transactions and rolling them back when complete.
The simple solution is to simply turn off transactions for integration tests, that solution will work but tends to lead to data pollution in downstream tests. Burt Beckwith has a solution in his post An Alternative Approach for Grails Integration Tests. Using this solution we can rebuild the database for each test.
In general most of the time you can use the default transactional testing behavior, therefore we want to only use this method some of the time. To achieve this effect we will modify Burt’s original solution slightly.
- Rebuild the database after each test
- Depend on the configured data source
- Update to Spock
You’ll notice we extend a company.IntegrationSpec there isn’t anything special in that just a base integration spec class that can hold our shared testing code such as bootstrapping methods and security methods. Since our data bootstrap logic is set up there we can share the same initial setup across both our normal integration test and our new non-transactional integration specs.
When to Use
The main time we started to need this new testing method was when doing custom propagation of hibernate transactions.
Since this will require a new transaction we will not be able to see the inserts that have happened in the default transaction. We do many of our reads as read only and force a new transaction when we are more read heavy during an operation.
In general anytime you are working directly with transaction rollbacks or propagation it best to test those things directly without having Grails inject an extra transaction in there for you.