feat(Registration): Validate user registration data

- Ensure that email submitted by user is correct
- Ensure that password is more than 8 characters and alphanumeric
- Ensure the the email used has not been used to create a previous account
- Ensure that the username is not already in use within the system

[Finishes #164069216]

authors/apps/authentication/serializers.py

@@ -15,7 +15,10 @@ class RegistrationSerializer(serializers.ModelSerializer):
     password = serializers.CharField(
         max_length=128,
         min_length=8,
-        write_only=True
+        write_only=True,
+        error_messages={
+            "min_length": "Password should be atleast {min_length} characters"
+        }
     )
 
     # The client should not be able to send a token along with a registration
@@ -45,20 +48,22 @@ def validate_email(self, value):
         return value
 
     def validate_username(self, value):
-        # validate that username passed is correct
+
         username_regex = (r'^[a-zA-Z]+$')
         data = self.get_initial()
         username = data.get("username")
         user_query_set = User.objects.filter(username=username)
 
+        # validate that username passed is correct
         if not re.search(username_regex, username):
-            raise serializers.ValidationError("The username is incorrect please use characters")
+            raise serializers.ValidationError(
+                "The username is invalid please use letters")
 
         if user_query_set.exists():
-            raise serializers.ValidationError("This username already exists please choose another one")
+            raise serializers.ValidationError(
+                "This username already exists please choose another one")
         return value
 
-
     def create(self, validated_data):
         # Use the `create_user` method we wrote earlier to create a new user.
         return User.objects.create_user(**validated_data)

authors/apps/authentication/tests/test_registration.py

@@ -24,22 +24,14 @@ def test_empty_username(self):
         self.assertEqual(
             response.data['errors']['username'][0], "This field may not be blank.")
 
-    def test_invalid_email(self):
-        """Tests if a user can not create an account with an invalid email."""
-
-        response = self.client.post(
-            self.registration_url, invalid_user_email, format='json')
-        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
-        self.assertEqual(
-            response.data['errors']['email'][0], "Enter a valid email address.")
 
     def test_short_password(self):
         """Tests if a user can not create an account with a short password."""
         response = self.client.post(
             self.registration_url, short_password, format='json')
         self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
         self.assertEqual(response.data['errors']['password']
-                         [0], "Ensure this field has at least 8 characters.")
+                         [0], "Password should be atleast 8 characters")
 
     def test_email_exits(self):
         """Tests if a user can not create an account with a taken email."""
@@ -51,6 +43,13 @@ def test_email_exits(self):
         self.assertEqual(
             response.data['errors']['email'][0], "user with this email already exists.")
 
+    def test_register_invalid_email(self):
+        response = self.client.post(
+            self.registration_url, invalid_user_email, format='json')
+        data = response.json().get('errors')
+        self.assertEqual(400, response.status_code)
+        self.assertIn('Enter a valid email address.', data['email'][0])
+
     def test_register_same_username(self):
         self.client.post(self.registration_url, valid_user, format='json')
         response = self.client.post(
@@ -60,3 +59,10 @@ def test_register_same_username(self):
         self.assertIn('user with this username already exists.',
                       data['username'])
 
+    def test_register_invalid_username(self):
+        response = self.client.post(
+            self.registration_url, invalid_username, format='json')
+        data = response.json().get('errors')
+        self.assertEqual(400, response.status_code)
+        self.assertIn('The username is invalid please use letters',
+                      data['username'])