testing grails data binding

Question

I've written the following Grails controller

class CategoryController {

    def create = {
        def newCategory = new CategoryCommand()
        bindData(newCategory, params)
        [newCategory: newCategory]
    }
}

class CategoryCommand {

    String name
    String seoName
}

I've written this unit test to test the data binding:

class CategoryControllerTests extends ControllerUnitTestCase {


    void testCreate() {

        // A new ControllerCommand should be returned if invoked with no params
        assertNotNull controller.create()

        // If called with params, they should be bound
        mockParams.name = 'snooker'
        mockParams.seoName = 'snooker-loopy'
        def model = controller.create()

        CategoryCommand newCategory = model.newCategory
        assertEquals 'snooker', newCategory.name
        assertEquals 'snooker-loopy', newCategory.seoName

    }
}

But I get this exception when controller.create() is invoked:

No signature of method: com.example.CategoryController.bindData() is applicable for argument types: (com.example.CategoryCommand, org.codehaus.groovy.grails.web.taglib.GroovyPageAttributes) values: [com.example.CategoryCommand@7860e7d2, [:]]

I tried running this as an integration test instead, but the result is the same.

Answer 1

Right...I did a bit of digging, and found this blog page which says (about half way down):

---

note:ControllerUnitTestCase not support some dynamic method. For instance: bindData(). Then is better use integration testing, or you can add this method to controller:

this.controller.metaClass.bindData = { obj, params ->  
  params.each { key, value ->  
    obj."$key" = value  
  }  
}  

---

Or, I had a look in the Grails source code, and to mock it to do the same as what Grails does, I think you'd need to do:

import org.codehaus.groovy.grails.web.metaclass.BindDynamicMethod

this.controller.metaClass.bindData = { obj, params ->
  new BindDynamicMethod().invoke( delegate, BindDynamicMethod.BIND_DATA_METHOD, [ obj, params ] as Object[] ) ;
}

(I think -- Not tested it tho)

Answer 2

As mentioned previously, mimicking Grails by using BindDynamicMethod works. This works for me on Grails 1.3.5:

import org.codehaus.groovy.grails.web.metaclass.BindDynamicMethod

protected void setUp() {
    def mc = controller.class.metaClass
    def bind = new BindDynamicMethod()
    mc.bindData = { Object target, Object args ->
        bind.invoke(delegate, "bindData", [ target, args ] as Object[])
    }
    mc.bindData = { Object target, Object args, List disallowed ->
        bind.invoke(delegate, "bindData", [ target, args, [ exclude: disallowed ]] as Object[])
    }
    mc.bindData = { Object target, Object args, List disallowed, String filter ->
        bind.invoke(delegate, "bindData", [ target, args, [ exclude: disallowed ], filter ] as Object[])
    }
    mc.bindData = { Object target, Object args, Map includeExclude ->
        bind.invoke(delegate, "bindData", [ target, args, includeExclude ] as Object[])
    }
    mc.bindData = { Object target, Object args, Map includeExclude, String filter ->
        bind.invoke(delegate, "bindData", [ target, args, includeExclude, filter ] as Object[])
    }
    mc.bindData = { Object target, Object args, String filter ->
        bind.invoke(delegate, "bindData", [ target, args, filter ] as Object[])
    }

}

This is copied from org/codehaus/groovy/grails/plugins/web/ControllersGrailsPlugin.groovy, and so it supports all forms of bindData.

Hopefully the situation will improve with the upcoming Grails 1.4 and testing mixins.