Give error if --run arg does not match a scenario

1 files changed, 4 insertions, 0 deletions

diff --git a/yarn b/yarn
index bcd22d3..3ca0bd5 100755
--- a/yarn
+++ b/yarn
@@ -292,6 +292,10 @@ class YarnRunner(cliapp.Application):
                     if matches(s.name, name) and s not in result:
                         result.append(s)
                         break
+                else:
+                    raise cliapp.AppException(
+                        'Requested scenario %s does not exist' %
+                        name)
             return result
 
         return scenarios