class Sus::Have::Key

def call(assertions, subject)
	# We want to group all the assertions in to a distinct group:
	assertions.nested(self, distinct: true) do |assertions|
		assertions.assert(subject.key?(@name), "has key")
		if @predicate
			Expect.new(assertions, subject[@name]).to(@predicate)
		end
	end
end

def initialize(name, predicate = nil)
	@name = name
	@predicate = predicate
end

def print(output)
	output.write("key ", :variable, @name.inspect, :reset, " ", @predicate, :reset)
end