add a test for InjectAt
add a test for InjectAt

jbowtie/gokogiri,moovweb/gokogiri,moovweb/gokogiri,ThomsonReutersEikon/gokogiri,jmcgill0brightcove/gokogiri,moovweb/gokogiri,ThomsonReutersEikon/gokogiri,jmcgill0brightcove/gokogiri,jbowtie/gokogiri,jmcgill0brightcove/gokogiri,jbowtie/gokogiri