--- a/testcases.py	Fri Apr 08 17:42:30 2011 +0300
+++ b/testcases.py	Fri Apr 08 17:45:53 2011 +0300
@@ -331,7 +331,11 @@
 				raise NonZeroExitCode(case.process.returncode)
 			case.has_called_back = True
 			callback()
-			with open(case.problem.config.outname, 'rU') as output:
+			try:
+				output = open(case.problem.config.outname, 'rU')
+			except IOError:
+				raise CannotReadOutputFile(sys.exc_info()[1])
+			with output as output:
 				return case.validate(output)
 
 
@@ -347,7 +351,11 @@
 		case.time_stopped = case.time_started = 0
 		case.has_called_back = True
 		callback()
-		with open(case.problem.config.outname.replace('$', case.id), 'rU') as output:
+		try:
+			output = open(case.problem.config.outname.replace('$', case.id), 'rU')
+		except IOError:
+			raise CannotReadOutputFile(sys.exc_info()[1])
+		with output as output:
 			return case.validate(output)