Fix 500 error on wrong definition

Closes-Bug: #1414921

Change-Id: I959e487006dee794ce74aa944291564a2c668b67

mistral/tests/unit/workbook/v2/test_dsl_specs_v2.py

@@ -158,6 +158,23 @@ workflows:
 """
 
 
+INVALID_WF = """
+--
+version: 2.0
+
+name: wb
+
+workflows:
+  wf1:
+    type: direct
+
+    tasks:
+      task1:
+        action: std.echo output="Hey!"
+
+"""
+
+
 # TODO(rakhmerov): Add more tests when v2 spec is complete.
 # TODO(rakhmerov): Add negative tests.
 
@@ -378,6 +395,14 @@ class DSLv2ModelTest(base.BaseTest):
         )
         self.assertIn("Wrong format of 'with-items'", str(exc))
 
+    def test_invalid_wf_spec(self):
+        exc = self.assertRaises(
+            exceptions.DSLParsingException,
+            spec_parser.get_workflow_spec_from_yaml,
+            INVALID_WF
+        )
+        self.assertIn("Definition could not be parsed", str(exc))
+
     def test_to_dict(self):
         wb_spec = spec_parser.get_workbook_spec_from_yaml(VALID_WB)
 

mistral/workbook/parser.py

@@ -42,7 +42,9 @@ def parse_yaml(text):
     try:
         return yaml.safe_load(text)
     except error.YAMLError as e:
-        raise RuntimeError("Definition could not be parsed: %s\n" % e)
+        raise exc.DSLParsingException(
+            "Definition could not be parsed: %s\n" % e
+        )
 
 
 def _get_spec_version(spec_dict):