Add python adapter error messages to score output

lib/py_unit_adapter.rb

@@ -1,6 +1,7 @@
 class PyUnitAdapter < TestingFrameworkAdapter
   COUNT_REGEXP = /Ran (\d+) test/
   FAILURES_REGEXP = /FAILED \(failures=(\d+)\)/
+  ASSERTION_ERROR_REGEXP = /AssertionError:\s(.*)/
 
   def self.framework_name
     'PyUnit'
@@ -10,6 +11,7 @@ class PyUnitAdapter < TestingFrameworkAdapter
     count = COUNT_REGEXP.match(output[:stderr]).captures.first.to_i
     matches = FAILURES_REGEXP.match(output[:stderr])
     failed = matches ? matches.captures.try(:first).to_i : 0
-    {count: count, failed: failed}
+    error_matches = ASSERTION_ERROR_REGEXP.match(output[:stderr]).captures
+    {count: count, failed: failed, error_messages: error_matches}
   end
 end