Unit testing rendered Json with JsonBuilder in Grails

Question

Let's say I have a simple action in my controller that ends with:

render(contentType: "text/json") {
    message = 'some text'
    foo = 'bar'
}

It renders correctly, as per the JSON builder documentation. However, when I attempt to unit test that response in a ControllerUnitTest, I get a blank string with controller.response.contentAsString. I even tried controller.renderArgs, but that just contains contentType: "text/json".

When I convert the JSON to a map, and marshall it as JSON, then I can test properly. But is there a way to unit test the code as it stands?

Answer 1

After much searching, I found that this is not possible in 1.3.7. Either have to upgrade to Grails 2.0, or override the controller metaClass as suggested in this post:

controller.class.metaClass.render = { Map map, Closure c ->
    renderArgs.putAll(map)

    switch(map["contentType"]) {
        case null:
            break

        case "application/xml":
        case "text/xml":
            def b = new StreamingMarkupBuilder()
            if (map["encoding"]) b.encoding = map["encoding"]

            def writable = b.bind(c)
            delegate.response.outputStream << writable
            break

        case "text/json":
            new JSonBuilder(delegate.response).json(c)
            break
        default:
            println "Nothing"
            break
    }
}