Grails Unit Testing for Beginners

When you use grails generators for domain classes, controllers, services or portlets, it automatically creates tests for you. Simply running "grails test-app" will run all unit and integration tests and is great for build processes. However, when you're developing you simply want to invoke the tests of the class you're editing. This can be accomplished by passing arguments to test-app like this:

grails test-app MyService -unit

or

grails test-app MyController -integration

Using println for testing is bad form but many times println in the code or tests is helpful for debugging. Grails generates test reports and one of them is the System.out. Open a tail tool (such as Baretail for Windows) on the file and you'll see the new results everytime the test runs (it does delete and replace the file.) These are located in:

my-app-home\target\test-reports\plain\
TEST-unit-unit-MyServiceTests.txt
TEST-unit-unit-MyServiceTests-err.txt
TEST-unit-unit-MyServiceTests-out.txt

You can also view an html report on the results of your tests. This is useful for seeing stacktraces:
my-app-home\target\test-reports\plain\index.html



-Ben Hidalgo