test fishshell/isatty/pty

-
	def:
		function testfunc
			if isatty 1
				set_color red
				echo "yup, i think i'm outputting to a tty (so this is color red) (argv is $argv)"
				set_color normal
			else
				echo "no, i think i'm *not* outputting to a tty (no color) (argv is $argv)"
			end
		end

	tests:
		> testfunc some args with spaces
			#=> yup, i think i'm outputting to a tty (so this is color red) (argv is some args with spaces)

		> testfunc some args with spaces|xargs -0 echo
			#=> no, i think i'm *not* outputting to a tty (no color) (argv is some args with spaces)

		> pty testfunc some args with spaces|xargs -0 echo
			#=> yup, i think i'm outputting to a tty (so this is color red) (argv is some args with spaces)


... wait, you mean problems like *this*, right?:

	def:
		function testfunc
			if isatty 1
				set_color red
				echo "yup, i think i'm outputting to a tty (so this is color red) (args are:   " (for i in (seq (count $argv)); echo -n "argv[$i]:$argv[$i]   " ;end) ")"
				set_color normal
			else
				echo "no, i think i'm *not* outputting to a tty (no color) (args are:   " (for i in (seq (count $argv)); echo -n "argv[$i]:$argv[$i]   " ;end) ")"
			end
		end

	tests:
		> testfunc "args with" 'spaces in them'
			#=> yup, i think i'm outputting to a tty (so this is color red) (args are:    argv[1]:args with   argv[2]:spaces in them    )
		> pty testfunc "args with" 'spaces in them'|xargs -0 echo
			#=> yup, i think i'm outputting to a tty (so this is color red) (args are:    argv[1]:args   argv[2]:with   argv[3]:spaces   argv[4]:in   argv[5]:them    )