Trouble Testing Tag That Interacts With pageScope

[sbglasius]

By @jeffbrown from grails/grails-core#9576 where it was closed.

It still seems to be an issue

package demo

class DemoTagLib {
    static namespace = 'demo'

    def putSomethingInPageScope = { attrs ->
        pageScope.someValue = attrs.foo
    }
}

package demo

import grails.test.mixin.TestFor
import spock.lang.Specification

@TestFor(DemoTagLib)
class DemoTagLibSpec extends Specification {

    void "use applyTemplate to test tag that puts something in pageScope"() {
        when:
        applyTemplate '<demo:putSomethingInPageScope foo="42"/>'

        then:
        tagLib.pageScope.someValue == '42'
    }

    void "use tag as method to test tag that puts something in pageScope"() {
        when:
        tagLib.putSomethingInPageScope(foo: '42')

        then:
        tagLib.pageScope.someValue == '42'
    }
}

The applyTemplate approach does not work. I think multiple pageScope (TemplateVariableBinding) objects are being created and the one populated by the tag is not the same one retrieved in the test.

[sbglasius]

Will this be looked at?

[sbglasius]

Ran into this again today.

[sbglasius]

@puneetbehl / @jeffbrown This is still a very frustrating problem. It's possible to write well-functional taglibs, but impossible to write a good test for them.

As far as I can tell, there are produced two page-bindings, one by org.grails.web.taglib.encoder.WebOutputContextLookup.WebOutputContext#createAndRegisterRootBinding and one by org.grails.gsp.GroovyPageWritable#doWriteTo (using the parent binding). It seems that the second created is the one used by the tag-lib, when accessing pageScope but for some reason, the applied template cannot find the variables written to it.

It looks like the method in org.grails.taglib.TemplateVariableBinding#getVariable is actually the one getting called by the tag-library, not org.grails.gsp.GroovyPageBinding#getVariable, but I have not been able to confirm this, and the reason.