Grails 3 Testing Hints/Tips

Grails 3.x changed a lot of things. Most for the good, but this introduced a number of changes in our test code.  Some of the misc hints/tips for testing are:

• Don't ever put @Integration in a test super-class.  Only use this in the concrete test classes.
• IDEA needs the tests to be marked with @Test to run in the IDEA/JUnit world.  Gradle can still run them, but the IDEA JUnit system misses them.
• Don't use @Rollback together with .withTransaction{} in most cases.  The .withTransaction{} gets rolled back too.
• Unit Tests need to use the save(flush:true)syntax now.
• For GEB testing of GUIs, never use @Transaction.  Instead use .withTransaction{} to create records.  The test code will not commit until it exits the method, so the server will never see the data while the test method is running.
• To test a controller in an integration test, you will need to send an HTTP request to the running server. I use HTTPClient for this.  A login is needed to do this (similar to GEB, but at the pure HTTP level, no GUI).
• application.groovy is needed for custom GORM data types.  The application.yml does not support the grails.gorm.default.mapping.user-type syntax needed for a custom user type.

(The last one is not test related, but I did not want to create a new blog post for it :).

Some of these could be bugs that might need fixes, but I am just not sure they are worth the time to fix them.  The work-arounds seem acceptable.