Fix syntax errors in test cases

test.py

@@ -58,7 +58,7 @@ class TestValidation(tornado.testing.AsyncHTTPTestCase):
         self.assertFalse(validation_result['valid'], "Validation result is expected to be valid==false")
 
     def test_valid_entity(self):
-        with open('test_cases/valid/valid.json', 'r') af f:
+        with open('test_cases/valid/valid.json', 'r') as f:
             entity_file = json.load(f)
 
         response = self.fetch('/v0/validate',
@@ -73,7 +73,7 @@ class TestValidation(tornado.testing.AsyncHTTPTestCase):
         self.assertTrue(validation_result['valid'], "Validation result is expected to be valid==true")
 
     def test_invalid_iban(self):
-        with open('test_cases/invalid/invalid_iban.json', 'r') af f:
+        with open('test_cases/invalid/invalid_iban.json', 'r') as f:
             entity_file = json.load(f)
 
         response = self.fetch('/v0/validate',
@@ -88,7 +88,7 @@ class TestValidation(tornado.testing.AsyncHTTPTestCase):
         self.assertFalse(validation_result['valid'], "Validation result is expected to be valid==false")
 
     def test_missing_id(self):
-        with open('test_cases/invalid/missing_id.json', 'r') af f:
+        with open('test_cases/invalid/missing_id.json', 'r') as f:
             entity_file = json.load(f)
 
         response = self.fetch('/v0/validate',
@@ -104,7 +104,7 @@ class TestValidation(tornado.testing.AsyncHTTPTestCase):
         self.assertIn('id', validation_result['errors'])
 
     def test_invalid_id(self):
-        with open('test_cases/invalid/invalid_id.json', 'r') af f:
+        with open('test_cases/invalid/invalid_id.json', 'r') as f:
             entity_file = json.load(f)
 
         response = self.fetch('/v0/validate',