[devtools] CubicWebTC._check_html may have to deal with unicode or bytes If called with template=None, CubicWebTC.view will not go through main-template, and return the unicode data from the view directly instead of encoded data.

if not rql('CWConstraintType X WHERE X name "RQLUniqueConstraint"',
           ask_confirm=False):
    rql('INSERT CWConstraintType X: X name "RQLUniqueConstraint"',
        ask_confirm=False)