Give an explicit error message when unsupported view type used

When specifying a view type that isn't supported by any modules (such as
"list-view" instead of "list"), this ensures that the user is guided
towards something correct.

This changes the error message in this case from:

AttributeError: 'NoneType' object has no attribute 'name'

to:

jenkins_jobs.errors.JenkinsJobsException: Unrecognized view type: list-view (supported types are: list, pipeline)

Change-Id: I0ee800db1c9c8aeecffcf11f1e86c03ba0590da8

jenkins_jobs/xml_config.py

@@ -123,6 +123,12 @@ class XmlViewGenerator(object):
             self._gen_xml(xml, data)
             view = XmlJob(xml, data['name'])
             return view
+        names = [
+            ep.name for ep in pkg_resources.iter_entry_points(
+                group='jenkins_jobs.views')]
+        raise errors.JenkinsJobsException(
+            'Unrecognized view type: {} (supported types are: {})'.format(
+                kind, ', '.join(names)))
 
     def _gen_xml(self, xml, data):
         for module in self.registry.modules:

tests/xml_config/exceptions/invalid_view.yaml

@@ -0,0 +1,3 @@
+- view:
+    name: invalid-view-type
+    view-type: invalid

tests/xml_config/test_xml_config.py

@@ -42,6 +42,22 @@ class TestXmlJobGeneratorExceptions(base.BaseTestCase):
                               xml_generator.generateXML, job_data)
         self.assertIn("Unrecognized project type:", str(e))
 
+    def test_invalid_view(self):
+        self.conf_filename = None
+        config = self._get_config()
+
+        yp = parser.YamlParser(config)
+        yp.parse(os.path.join(self.fixtures_path, "invalid_view.yaml"))
+
+        reg = registry.ModuleRegistry(config)
+        _, view_data = yp.expandYaml(reg)
+
+        # Generate the XML tree
+        xml_generator = xml_config.XmlViewGenerator(reg)
+        e = self.assertRaises(errors.JenkinsJobsException,
+                              xml_generator.generateXML, view_data)
+        self.assertIn("Unrecognized view type:", str(e))
+
     def test_incorrect_template_params(self):
         self.conf_filename = None
         config = self._get_config()