Grails 2.1 Unit Testing Command Object mockForConstraintsTests not working?

Question

I have used manually written as well as Grails generated Unit tests for this command object:

   package myapp

    @grails.validation.Validateable
    class SearchCommand {
       String basisBuild
       String buildToSearch

       static constraints = {
          basisBuild(blank: false)
       }
    }

After having my hand written unit test fail I used Grails:

create-unit-test  myapp.SearchCommand

I filled in the Unit Test, and made an assertion that should pass per documentation on mocked constraints:

package myapp
import static org.junit.Assert.*

import grails.test.mixin.*
import grails.test.mixin.support.*
import org.junit.*

@TestMixin(GrailsUnitTestMixin)
class SearchCommandTests {

    void setUp() {
        mockForConstraintsTests(SearchCommand)
    }

    void tearDown() {
        // Tear down logic here
    }

    void testSomething() {
        SearchCommand commandUnderTest = new SearchCommand()

        commandUnderTest.validate(basisBuild: "")

        assertEquals "blank", commandUnderTest.errors['basisBuild']
    }
}

Why am I getting this failure?

grails> test-app
| Running 9 unit tests... 9 of 9
| Failure:  testSomething(com.siemens.soarian.sf.gap.SearchCommandTests)
|  java.lang.AssertionError: expected:<blank> but was:<null>
        at org.junit.Assert.fail(Assert.java:93)

Answer 1

I believe I found the grails supported way to unit test Command objects in grails 2.0. You need to use mockCommandObject provided by the ControllerUnitTestMixin.

Credit to Erik

http://www.jworks.nl/2012/04/12/testing-command-objects-in-grails-2-0/

Answer 2

EDIT

Using validate() appropriately and mockForConstraintsTest should work if the patch mentioned in the existing Grails bug is in place (Thanks to @codelark for bringing that up). In order to test the command object from a Web App standpoint (using controller) the below information would be helpful.

Test Command Object Using Controller action:-

A command object is only deemed as such when it is used as a parameter in one of the action method inside a controller. Refer Command Objects (Warning NOTE). Use SearchCommand in an action method, you should be able to assertEquals.

Sample:

void testSomething() {
        YourController controller = mockController(YourController) //Or instantiate
        SearchCommand commandUnderTest = new SearchCommand ()
        //Note the usage here. validate() does not take parameters
        commandUnderTest.basisBuild = ''
        commandUnderTest.validate()

        //Call your action
        controller.searchCommandAction(commandUnderTest)

        assert response.text == 'Returned'
        assertEquals "blank", commandUnderTest.errors['basisBuild']
    }

YourController's action:-

def searchCommandAction(SearchCommand sc){
    render "Returned"
}

Note:

With out the patch from the grails bug we see the below error in @Grails 2.1.4, 2.2.0 & 2.2.1

I get an error when I only correct the validation and use mockForConstraintTests without using controller action:

Answer 3

You are using the validate method incorrectly. You never set the field on the class, so the field is null, not blank. Try changing your test as follows:

void testSomething() {
    SearchCommand commandUnderTest = new SearchCommand()
    commandUnderTest.basisBuild = ""

    assertFalse commandUnderTest.validate()
    assertEquals 'blank', commandUnderTest.errors['basisBuild']
}

Edit: There is also a grails bug when testing command classes that use the @Validatable annotation. There are some workarounds in the bug commentary.