Test Adapters: Always use the last output for score runs

* This prevents learners from cheating by printing the required status line themselves

lib/mocha_adapter.rb

@@ -9,10 +9,8 @@ class MochaAdapter < TestingFrameworkAdapter
   end
 
   def parse_output(output)
-    matches_success = SUCCESS_REGEXP.match(output[:stdout])
-    matches_failed = FAILURES_REGEXP.match(output[:stdout])
-    failed = matches_failed ? matches_failed.captures.first.to_i : 0
-    success = matches_success ? matches_success.captures.first.to_i : 0
+    success = output[:stdout].scan(SUCCESS_REGEXP).try(:last).try(:first).try(:to_i) || 0
+    failed = output[:stdout].scan(FAILURES_REGEXP).try(:last).try(:first).try(:to_i) || 0
     {count: success + failed, failed: failed}
   end
 end