Add core util tests - camelcase_to_underscore
Add core util tests - camelcase_to_underscore

kaedroho/wagtail,jnns/wagtail,zerolab/wagtail,torchbox/wagtail,FlipperPA/wagtail,mixxorz/wagtail,jnns/wagtail,kaedroho/wagtail,thenewguy/wagtail,jnns/wagtail,thenewguy/wagtail,rsalmaso/wagtail,torchbox/wagtail,rsalmaso/wagtail,wagtail/wagtail,zerolab/wagtail,mixxorz/wagtail,FlipperPA/wagtail,zerolab/wagtail,takeflight/wagtail,mixxorz/wagtail,wagtail/wagtail,kaedroho/wagtail,torchbox/wagtail,gasman/wagtail,mixxorz/wagtail,thenewguy/wagtail,kaedroho/wagtail,FlipperPA/wagtail,gasman/wagtail,zerolab/wagtail,takeflight/wagtail,rsalmaso/wagtail,torchbox/wagtail,takeflight/wagtail,jnns/wagtail,gasman/wagtail,thenewguy/wagtail,thenewguy/wagtail,rsalmaso/wagtail,gasman/wagtail,gasman/wagtail,FlipperPA/wagtail,mixxorz/wagtail,zerolab/wagtail,wagtail/wagtail,rsalmaso/wagtail,takeflight/wagtail,kaedroho/wagtail,wagtail/wagtail,wagtail/wagtail