diff --git a/ckan/templates/tests/mock_json_resource_preview_template.html b/ckan/templates/tests/mock_json_resource_preview_template.html
new file mode 100644
index 00000000000..e5e9fa04975
--- /dev/null
+++ b/ckan/templates/tests/mock_json_resource_preview_template.html
@@ -0,0 +1,17 @@
+{% extends 'dataviewer/base.html' %}
+
+{% block page %}
+  <div>
+    <pre data-module="mock-json-preview">
+      <div class="loading">
+        {{ _('Loading...') }}
+      </div>
+    </pre>
+  </div>
+{% endblock %}
+
+{% block scripts %}
+  {{ super() }}
+
+  <script src="mock-json-preview.js" ?>
+{% endblock %}
diff --git a/ckan/tests/functional/test_preview_interface.py b/ckan/tests/functional/test_preview_interface.py
index 86e0b8b73b9..b4b8f3d8982 100644
--- a/ckan/tests/functional/test_preview_interface.py
+++ b/ckan/tests/functional/test_preview_interface.py
@@ -1,10 +1,12 @@
 from ckan.tests import *
 import ckan.lib.helpers as h
+import ckan.logic as l
 import ckan.model as model
 from ckan.lib.create_test_data import CreateTestData
 from ckan.tests.functional.base import FunctionalTestCase
 import ckan.plugins as plugins
 import ckan.tests.mock_plugin as mock
+from ckan.lib.dictization.model_dictize import resource_dictize
 
 
 class MockResourcePreviewExtension(mock.MockSingletonPlugin):
@@ -16,7 +18,7 @@ def __init__(self):
 
     def can_preview(self, data_dict):
         self.calls['can_preview'] += 1
-        return True
+        return data_dict['resource']['format'].lower() == 'mock'
 
     def setup_template_variables(self, context, data_dict):
         self.calls['setup_template_variables'] += 1
@@ -26,11 +28,23 @@ def preview_template(self, context, data_dict):
         return 'tests/mock_resource_preview_template.html'
 
 
+class JsonMockResourcePreviewExtension(MockResourcePreviewExtension):
+    def can_preview(self, data_dict):
+        return data_dict['resource']['format'].lower() == 'json'
+
+    def preview_template(self, context, data_dict):
+        self.calls['preview_templates'] += 1
+        return 'tests/mock_json_resource_preview_template.html'
+
+
 class TestPluggablePreviews(FunctionalTestCase):
     @classmethod
     def setup_class(cls):
         cls.plugin = MockResourcePreviewExtension()
         plugins.load(cls.plugin)
+        json_plugin = JsonMockResourcePreviewExtension()
+        plugins.load(json_plugin)
+
         CreateTestData.create()
 
     @classmethod
@@ -39,26 +53,24 @@ def teardown_class(cls):
         plugins.unload(cls.plugin)
 
     def test_hook(self):
-        '''
-        TODO:
-            * Modify mock plugin to only preview resources of type 'mock'
-            * Create a dataset with two resources (logic function), one of type mock and one
-            of another type, and check that the mock stuff is only rendered on
-            the relevant one and not the other
-            * (?) create resources of type csv, json and pdf and look if the relevant bits
-            are rendered (these tests should probably go in their relevant extensions)
-
-        '''
-
+        testpackage = model.Package.get('annakarenina')
+        resource_dict = resource_dictize(testpackage.resources[0], {'model': model})
+        resource_dict['format'] = 'mock'
 
+        context = {
+            'model': model,
+            'session': model.Session,
+            'user': model.User.get('testsysadmin').name
+        }
 
-        testpackage = model.Package.get('annakarenina')
+        l.action.update.resource_update(context, resource_dict)
+        print testpackage.resources[0].format
 
-        offset = h.url_for(controller='package',
+        preview_url = h.url_for(controller='package',
                 action='resource_datapreview',
                 id=testpackage.id,
                 resource_id=testpackage.resources[0].id)
-        result = self.app.get(offset, status=200)
+        result = self.app.get(preview_url, status=200)
 
         assert 'mock-preview' in result.body
         assert 'mock-preview.js' in result.body
@@ -66,3 +78,14 @@ def test_hook(self):
         assert self.plugin.calls['can_preview'] == 1, plugin.call
         assert self.plugin.calls['setup_template_variables'] == 1, plugin.calls
         assert self.plugin.calls['preview_templates'] == 1, plugin.calls
+
+        preview_url = h.url_for(controller='package',
+                action='resource_datapreview',
+                id=testpackage.id,
+                resource_id=testpackage.resources[1].id)
+        result = self.app.get(preview_url, status=200)
+
+        assert 'mock-preview' not in result.body, result.body
+        assert 'mock-preview.js' not in result.body, result.body
+        assert 'mock-json-preview' in result.body
+        assert 'mock-json-preview.js' in result.body