List of available tests:

- core:network
	Arguments: network to look for
	Test: checks whether the "core:network" variable is currently
	set to the argument. If so, returns success; if not, returns
	failure.
	Side-effects: none
	Implemented by: core
	TODO: This should actively search for a network, rather than
	passively.
- core:mii
	Arguments: none
	Test: checks whether the interface has a link.
	Side-effects: brings the interface up
	Implemented by: backend
	TODO: undo side-effect if no link was found, undo side-effect on
	down.
- core:isup
	Arguments: optionally, interface name
	Test/up: checks whether the current or specified interface is
	physically up. Does not check for IP address
	Test/down: none
	Side-effects: none
	Implemented by: backend
	TODO: check for IP address
- core:value
	Arguments: context variable name, value
	Test: runs strcmp() on the value of the given context variable
	and the second argument.
	Side-effects: none
	Implemented by: core
- core:indirect_value
	Arguments: two context variable names
	Test: runs strcmp() on the values of the two given context
	variable names
	Side-effects: none
	Implemented by: core
- wireless:essidlist
	Arguments: list of networks to scan for
	Test: compares the given list of networks in asciibetical order
	against the list of networks that can be found by an active
	scan.
	Side-effects: brings the interface up. Sets the "wireless:essid"
	variable to the ESSID found.
	Implemented by: module "wireless"
	TODO: alternative version that allows better ordering
