Test ERB files for string interpolation too
Test ERB files for string interpolation too

fixes https://github.com/opal/opal/issues/719
iliabylich/opal,opal/opal,jgaskins/opal,iliabylich/opal,Mogztter/opal,kachick/opal,Mogztter/opal,Mogztter/opal,kachick/opal,opal/opal,opal/opal,iliabylich/opal,jgaskins/opal,opal/opal,jgaskins/opal,Mogztter/opal,kachick/opal,kachick/opal