also str representation of unicode character is different.

/reviewed-on nexedi/erp5!1757

In nexedi/erp5@79fa584e we moved
some security definition from wendelin to erp5, but we didn't add any
tests anywhere. Recent project based tests revealed that this
migration actually failed [1]. We should therefore add a test for
this.

[1] nexedi/wendelin@f8678468 (comment 181134)

/reviewed-on nexedi/erp5!1757