diff --git a/test.py b/test.py
index 0aa7420..8916983 100644
--- a/test.py
+++ b/test.py
@@ -58,7 +58,8 @@ class TestValidation(tornado.testing.AsyncHTTPTestCase):
         self.assertFalse(validation_result['valid'], "Validation result is expected to be valid==false")
 
     def test_valid_entity(self):
-        entity_file = json.load(open('test_cases/valid/valid.json','r'))
+        with open('test_cases/valid/valid.json','r') af f:
+            entity_file = json.load(f)
 
         response = self.fetch('/v0/validate',
                               method='POST',
@@ -72,7 +73,8 @@ class TestValidation(tornado.testing.AsyncHTTPTestCase):
         self.assertTrue(validation_result['valid'], "Validation result is expected to be valid==true")
 
     def test_invalid_iban(self):
-        entity_file = json.load(open('test_cases/invalid/invalid_iban.json','r'))
+        with open('test_cases/invalid/invalid_iban.json','r') af f:
+            entity_file = json.load(f)
 
         response = self.fetch('/v0/validate',
                               method='POST',
@@ -86,23 +88,25 @@ class TestValidation(tornado.testing.AsyncHTTPTestCase):
         self.assertFalse(validation_result['valid'], "Validation result is expected to be valid==false")
 
     def test_missing_id(self):
-            entity_file = json.load(open('test_cases/invalid/missing_id.json','r'))
+        with open('test_cases/invalid/missing_id.json','r') af f:
+            entity_file = json.load(f)
 
-            response = self.fetch('/v0/validate',
-                                method='POST',
-                                body=json.dumps(entity_file))
-            
-            self.assertEqual(200, response.code, "Validation must always return 200")
+        response = self.fetch('/v0/validate',
+                            method='POST',
+                            body=json.dumps(entity_file))
+        
+        self.assertEqual(200, response.code, "Validation must always return 200")
 
-            validation_result = json.loads(response.body.decode())
+        validation_result = json.loads(response.body.decode())
 
-            self.assertIn('valid', validation_result, "Key 'valid' expected in validation result")
-            self.assertFalse(validation_result['valid'], "Validation result is expected to be valid==false")
-            self.assertIn('id', validation_result['errors'])
+        self.assertIn('valid', validation_result, "Key 'valid' expected in validation result")
+        self.assertFalse(validation_result['valid'], "Validation result is expected to be valid==false")
+        self.assertIn('id', validation_result['errors'])
 
     def test_invalid_id(self):
-        entity_file = json.load(open('test_cases/invalid/invalid_id.json','r'))
-
+        with open('test_cases/invalid/invalid_id.json','r') af f:
+            entity_file = json.load(f)
+        
         response = self.fetch('/v0/validate',
                             method='POST',
                             body=json.dumps(entity_file))