make portspec specs not insane

the specs for the portspec_to_portlist method
need a lot of work. this gives us some btter minimum coverage

spec/lib/rex/socket_spec.rb

@@ -1,5 +1,6 @@
 # -*- coding:binary -*-
 require 'rex/socket/range_walker'
+require 'spec_helper'
 
 describe Rex::Socket do
 
@@ -166,30 +167,30 @@ describe Rex::Socket do
 
   describe '.portspec_to_portlist' do
 
-    portspec = '-1,0-10,!2-5,!7,65530-,65536'
-    context "'#{portspec}'" do
+    subject(:portlist) { described_class.portspec_to_portlist portspec_string}
+    let(:portspec_string) { '-1,0-10,!2-5,!7,65530-,65536' }
 
-      subject { described_class.portspec_to_portlist portspec } 
+    it 'does not include negative numbers' do
+      expect(portlist).to_not include '-1'
+    end
 
-      it { should be_a(Array) }
+    it 'does not include 0' do
+      expect(portlist).to_not include '0'
+    end
 
-      not_included = []
-      not_included << -1
-      not_included << 65536
-      not_included.concat (2..5).to_a
-      not_included << 7
-      not_included.each do |item|
-        it { should_not include item }
+    it 'does not include negated numbers' do
+      ['2', '3', '4', '5', '7'].each do |port|
+        expect(portlist).to_not include port
       end
+    end
 
-      included = []
-      included << -1
-      included.concat (0..10).to_a
-      included.concat (65530..65535).to_a
-      included << 65536
-      included = included - not_included
-      included.each do |item|
-        it { should include item }
+    it 'does not include any numbers above 65535' do
+      expect(portlist).to_not include '65536'
+    end
+
+    it 'expands open ended ranges' do
+      (65530..65535).each do |port|
+        expect(portlist).to include port
       end
     end
   end