added field old_password to endpoint for change user password

apps/account/serializers/common.py

@@ -1,5 +1,6 @@
 """Common account serializers"""
 from django.conf import settings
+from django.utils.translation import gettext_lazy as _
 from django.contrib.auth import password_validation as password_validators
 from fcm_django.models import FCMDevice
 from rest_framework import exceptions
@@ -80,23 +81,31 @@ class ChangePasswordSerializer(serializers.ModelSerializer):
     """Serializer for model User."""
 
     password = serializers.CharField(write_only=True)
+    old_password = serializers.CharField(write_only=True)
 
     class Meta:
         """Meta class"""
         model = models.User
-        fields = ('password', )
+        fields = (
+            'password',
+            'old_password',
+        )
 
     def validate(self, attrs):
         """Override validate method"""
         password = attrs.get('password')
+        old_password = attrs.get('old_password')
         try:
+            # Check old password
+            if not self.instance.check_password(raw_password=old_password):
+                raise serializers.ValidationError(_('Old password mismatch.'))
             # Compare new password with the old ones
             if self.instance.check_password(raw_password=password):
-                raise utils_exceptions.PasswordsAreEqual()
+                raise serializers.ValidationError(_('Password is already in use'))
             # Validate password
             password_validators.validate_password(password=password)
         except serializers.ValidationError as e:
-            raise serializers.ValidationError(str(e))
+            raise serializers.ValidationError({'detail': e.detail})
         else:
             return attrs