fails:IO.popen with a leading Array parameter uses a trailing Hash in the Array for spawn-like settings
fails:IO.popen with a leading ENV Hash accepts an Array command with a separate trailing Hash of Process.exec options
fails:IO.popen with a leading ENV Hash accepts an Array command with a separate trailing Hash of Process.exec options, and an IO mode
fails:IO.popen with a leading Array argument accepts a trailing Hash of Process.exec options
fails:IO.popen with a leading Array argument accepts an IO mode argument following the Array
fails:IO.popen with a leading Array argument accepts [env, command, arg1, arg2, ..., exec options]
fails:IO.popen with a leading Array argument accepts '[env, command, arg1, arg2, ..., exec options], mode'
fails:IO.popen with a leading Array argument accepts '[env, command, arg1, arg2, ..., exec options], mode, IO options'
fails:IO.popen with a leading Array argument accepts '[env, command, arg1, arg2, ...], mode, IO + exec options'
fails:IO.popen with a leading ENV Hash accepts a single String command with a trailing Hash of Process.exec options
fails:IO.popen with a leading ENV Hash accepts a single String command with a trailing Hash of Process.exec options, and an IO mode
