Skip packages resource for unsupported OS

Signed-off-by: Alex Pop <apop@chef.io>

lib/resources/packages.rb

@@ -23,10 +23,14 @@ module Inspec::Resources
     "
 
     def initialize(pattern)
+      @command = packages_command
+
+      return skip_resource "The packages resource is not yet supported on OS #{inspec.os.name}" unless @command
+
       @pattern = pattern_regexp(pattern)
-      all_pkgs = package_list
+      all_pkgs = build_package_list(@command)
       @list = all_pkgs.find_all do |hm|
-        hm[:name] =~ pattern_regexp(pattern)
+        hm[:name] =~ @pattern
       end
     end
 
@@ -44,31 +48,29 @@ module Inspec::Resources
 
     private
 
+    def packages_command
+      os = inspec.os
+      if os.debian?
+        command = "dpkg-query -W -f='${db:Status-Abbrev} ${Package} ${Version}\\n'"
+      end
+      command
+    end
+
     def pattern_regexp(p)
       if p.class == String
         Regexp.new(Regexp.escape(p))
       elsif p.class == Regexp
         p
       else
-        raise 'invalid name argument to packages resource, please use a "string" or /regexp/'
+        raise 'Invalid name argument to packages resource, please use a "string" or /regexp/'
       end
     end
 
     def filtered_packages
+      warn "The packages resource is not yet supported on OS #{inspec.os.name}" unless @command
       @list
     end
 
-    def package_list
-      os = inspec.os
-
-      if os.debian?
-        command = "dpkg-query -W -f='${db:Status-Abbrev} ${Package} ${Version}\\n'"
-      else
-        raise "packages resource is not yet supported on #{os.name}"
-      end
-      build_package_list(command)
-    end
-
     Package = Struct.new(:status, :name, :version)
 
     def build_package_list(command)

lib/resources/users.rb

@@ -57,7 +57,7 @@ module Inspec::Resources
     name 'users'
     desc 'Use the users InSpec audit resource to test local user profiles. Users can be filtered by groups to which they belong, the frequency of required password changes, the directory paths to home and shell.'
     example "
-      describe users.where(uid: 0).entries do
+      describe users.where { uid == 0 }.entries do
         it { should eq ['root'] }
         its('uids') { should eq [1234] }
         its('gids') { should eq [1234] }

test/unit/resources/packages_test.rb

@@ -43,11 +43,9 @@ describe 'Inspec::Resources::Packages' do
   end
 
 
-  it 'fails on non debian platforms' do
-    proc {
-      resource = MockLoader.new(:centos6).load_resource('packages', 'bash')
-      resource.send(:entries, nil)
-    }.must_raise(RuntimeError)
+  it 'skips on non debian platforms' do
+    resource = MockLoader.new(:centos6).load_resource('packages', [:a, :b])
+    _(resource.resource_skipped).must_equal 'The packages resource is not yet supported on OS centos'
   end
 
   it 'fails if the packages name is not a string or regexp' do