Fail tests for dirty tracking type casting

@byroot @qq99

These tests show this failure:

```
[12] pry> shop.password_enabled?
=> false
[13] pry> shop.password_enabled = "false"
=> "false"
[14] pry> shop.password_enabled?
=> false
[15] pry> shop.password_enabled_changed?
=> true
```
Tests will need to be updated, but for now.

Don't know if this will mess with Travis though.