Correct validation of wait conditon

This changes:
1. if the referenced wait condition is invalid,
   return '' when resolve attribute.
2. if the referenced wait condition is invalid,
   raise error with correct message.

Closes-Bug: #1666747

Change-Id: I69248c2bd80246ea6d08c1f140885e4b461353a0

heat/engine/resources/openstack/heat/wait_condition.py

@@ -92,9 +92,12 @@ class HeatWaitCondition(resource.Resource):
         return self.stack.resource_by_refid(self.properties[self.HANDLE])
 
     def _validate_handle_resource(self, handle):
-        if not isinstance(handle, wc_base.BaseWaitConditionHandle):
+        if handle is not None and isinstance(
-            raise ValueError(_('%(name)s is not a valid wait condition '
+                handle, wc_base.BaseWaitConditionHandle):
-                               'handle.') % {'name': handle.name})
+            return
+        hn = handle.name if handle else self.properties[self.HANDLE]
+        msg = _('%s is not a valid wait condition handle.') % hn
+        raise ValueError(msg)
 
     def _wait(self, handle, started_at, timeout_in):
         if timeutils.is_older_than(started_at, timeout_in):
@@ -144,6 +147,8 @@ class HeatWaitCondition(resource.Resource):
 
     def _resolve_attribute(self, key):
         handle = self._get_handle_resource()
+        if handle is None:
+            return ''
         if key == self.DATA:
             meta = handle.metadata_get(refresh=True)
             res = {k: meta[k][handle.DATA] for k in meta}

heat/tests/openstack/heat/test_waitcondition.py

@@ -108,7 +108,7 @@ resources:
         type: OS::Heat::UpdateWaitConditionHandle
 '''
 
-test_template_bad_waithandle = '''
+test_template_waithandle_bad_type = '''
 heat_template_version: 2013-05-23
 resources:
     wait_condition:
@@ -120,6 +120,20 @@ resources:
         type: OS::Heat::RandomString
 '''
 
+test_template_waithandle_bad_reference = '''
+heat_template_version: pike
+resources:
+    wait_condition:
+        type: OS::Heat::WaitCondition
+        properties:
+            handle: wait_handel
+            timeout: 5
+    wait_handle:
+        type: OS::Heat::WaitConditionHandle
+        properties:
+            signal_transport: NO_SIGNAL
+'''
+
 
 class HeatWaitConditionTest(common.HeatTestCase):
 
@@ -206,17 +220,24 @@ class HeatWaitConditionTest(common.HeatTestCase):
         self.assertEqual('wait_handle', r.name)
         self.m.VerifyAll()
 
-    def test_bad_wait_handle(self):
+    def _test_wait_handle_invalid(self, tmpl, handle_name):
-        self.stack = self.create_stack(
+        self.stack = self.create_stack(template=tmpl)
-            template=test_template_bad_waithandle)
         self.m.ReplayAll()
         self.stack.create()
         rsrc = self.stack['wait_condition']
         self.assertEqual((rsrc.CREATE, rsrc.FAILED), rsrc.state)
         reason = rsrc.status_reason
-        self.assertEqual(reason, 'ValueError: resources.wait_condition: '
+        error_msg = ('ValueError: resources.wait_condition: '
-                                 'wait_handle is not a valid wait condition '
+                     '%s is not a valid wait condition handle.') % handle_name
-                                 'handle.')
+        self.assertEqual(reason, error_msg)
+
+    def test_wait_handle_bad_type(self):
+        self._test_wait_handle_invalid(test_template_waithandle_bad_type,
+                                       'wait_handle')
+
+    def test_wait_handle_bad_reference(self):
+        self._test_wait_handle_invalid(
+            test_template_waithandle_bad_reference, 'wait_handel')
 
     def test_timeout(self):
         self.stack = self.create_stack()