diff --git a/lib/puppet/provider.rb b/lib/puppet/provider.rb
index ca401014e..578d4a972 100644
--- a/lib/puppet/provider.rb
+++ b/lib/puppet/provider.rb
@@ -1,314 +1,369 @@
 # The container class for implementations.
 class Puppet::Provider
   include Puppet::Util::Execution
   include Puppet::Util
   include Puppet::Util::Errors
   include Puppet::Util::Warnings
   extend Puppet::Util::Warnings
 
   require 'puppet/provider/confiner'
   require 'puppet/provider/command'
 
   extend Puppet::Provider::Confiner
 
   Puppet::Util.logmethods(self, true)
 
   class << self
     # Include the util module so we have access to things like 'which'
     include Puppet::Util, Puppet::Util::Docs
     include Puppet::Util::Logging
     attr_accessor :name
 
     # The source parameter exists so that providers using the same
     # source can specify this, so reading doesn't attempt to read the
     # same package multiple times.
     attr_writer :source
 
     # LAK 2007-05-09: Keep the model stuff around for backward compatibility
     attr_reader :model
     attr_accessor :resource_type
     attr_writer :doc
   end
 
   # LAK 2007-05-09: Keep the model stuff around for backward compatibility
   attr_reader :model
   attr_accessor :resource
 
   def self.command(name)
     name = symbolize(name)
 
     if defined?(@commands) and command = @commands[name]
       # nothing
     elsif superclass.respond_to? :command and command = superclass.command(name)
       # nothing
     else
       raise Puppet::DevError, "No command #{name} defined for provider #{self.name}"
     end
 
     which(command)
   end
 
   # Define commands that are not optional.
   #
-  # @param [Hash{String => String, Puppet::Provider::Command}] command_specs Named commands that the provider will 
-  #   be executing on the system. Each command is specified with a name and the path of the executable or a 
-  #   Puppet::Provider::Command object.
+  # @param [Hash{String => String}] command_specs Named commands that the provider will 
+  #   be executing on the system. Each command is specified with a name and the path of the executable.
+  # (@see #has_command)
   def self.commands(command_specs)
-    optional_commands(command_specs) do |name, path|
-      confine :exists => path, :for_binary => true
+    command_specs.each do |name, path|
+      has_command(name, path)
+    end
+  end
+
+  # Define commands that are optional.
+  #
+  # @param [Hash{String => String}] command_specs Named commands that the provider will 
+  #   be executing on the system. Each command is specified with a name and the path of the executable.
+  # (@see #has_command)
+  def self.optional_commands(hash)
+    hash.each do |name, target|
+      has_command(name, target) do
+        is_optional
+      end
+    end
+  end
+
+  # Define a single command
+  #
+  # A method will be generated on the provider that allows easy execution of the command. The generated 
+  # method can take arguments that will be passed through to the executable as the command line arguments 
+  # when it is run.
+  #
+  #     has_command(:echo, "/bin/echo")
+  #     def some_method
+  #       echo("arg 1", "arg 2")
+  #     end
+  #
+  #     # or
+  #
+  #     has_command(:echo, "/bin/echo") do
+  #       is_optional
+  #       environment :HOME => "/var/tmp", :PWD => "/tmp"
+  #     end
+  #
+  # @param [Symbol] name Name of the command (will be the name of the generated method to call the command)
+  # @param [String] path The path to the executable for the command
+  # @yield A block that configures the command (@see Puppet::Provider::Command) 
+  def self.has_command(name, path, &block)
+    name = symbolize(name)
+    configuration = block_given? ? block : Proc.new {}
+    command = CommandDefiner.new(name, path, self, &configuration).command
+
+    @commands[name] = command.executable
+
+    # Now define the class and instance methods.
+    create_class_and_instance_method(name) do |*args|
+      return command.execute(name, Puppet::Util, Puppet::Util::Execution, *args)
+    end
+  end
+
+  class CommandDefiner
+    def initialize(name, path, confiner, &block)
+      @name = name
+      @path = path
+      @optional = false
+      @confiner = confiner
+      @custom_environment = {}
+
+      instance_eval &block
+    end
+
+    def is_optional
+      @optional = true
+    end
+
+    def environment(env)
+      @custom_environment = @custom_environment.merge(env)
+    end
+
+    def command
+      if not @optional
+        @confiner.confine :exists => @path, :for_binary => true
+      end
+
+      Puppet::Provider::Command.new(@path, { :custom_environment => @custom_environment })
     end
   end
 
   # Is the provided feature a declared feature?
   def self.declared_feature?(name)
     defined?(@declared_features) and @declared_features.include?(name)
   end
 
   # Does this implementation match all of the default requirements?  If
   # defaults are empty, we return false.
   def self.default?
     return false if @defaults.empty?
     if @defaults.find do |fact, values|
         values = [values] unless values.is_a? Array
         if fval = Facter.value(fact).to_s and fval != ""
           fval = fval.to_s.downcase.intern
         else
           return false
         end
 
         # If any of the values match, we're a default.
         if values.find do |value| fval == value.to_s.downcase.intern end
           false
         else
           true
         end
       end
       return false
     else
       return true
     end
   end
 
   # Store how to determine defaults.
   def self.defaultfor(hash)
     hash.each do |d,v|
       @defaults[d] = v
     end
   end
 
   def self.specificity
     (@defaults.length * 100) + ancestors.select { |a| a.is_a? Class }.length
   end
 
   def self.initvars
     @defaults = {}
     @commands = {}
   end
 
   # The method for returning a list of provider instances.  Note that it returns providers, preferably with values already
   # filled in, not resources.
   def self.instances
     raise Puppet::DevError, "Provider #{self.name} has not defined the 'instances' class method"
   end
 
   # Create the methods for a given command.
   #
   # @deprecated Use {#commands} or {#optional_commands} instead. This was not meant to be part of a public API
   def self.make_command_methods(name)
     Puppet.deprecation_warning "Provider.make_command_methods is deprecated; use Provider.commands or Provider.optional_commands instead for creating command methods"
 
     # Now define a method for that command
     unless singleton_class.method_defined?(name)
       meta_def(name) do |*args|
         # This might throw an ExecutionFailure, but the system above
         # will catch it, if so.
         command = Puppet::Provider::Command.new(command(name))
         return command.execute(name, Puppet::Util, Puppet::Util::Execution, *args)
       end
 
       # And then define an instance method that just calls the class method.
       # We need both, so both instances and classes can easily run the commands.
       unless method_defined?(name)
         define_method(name) do |*args|
           self.class.send(name, *args)
         end
       end
     end
   end
 
   # Create getter/setter methods for each property our resource type supports.
   # They all get stored in @property_hash.  This method is useful
   # for those providers that use prefetch and flush.
   def self.mkmodelmethods
     Puppet.deprecation_warning "Provider.mkmodelmethods is deprecated; use Provider.mk_resource_methods"
     mk_resource_methods
   end
 
   # Create getter/setter methods for each property our resource type supports.
   # They all get stored in @property_hash.  This method is useful
   # for those providers that use prefetch and flush.
   def self.mk_resource_methods
     [resource_type.validproperties, resource_type.parameters].flatten.each do |attr|
       attr = symbolize(attr)
       next if attr == :name
       define_method(attr) do
         @property_hash[attr] || :absent
       end
 
       define_method(attr.to_s + "=") do |val|
         @property_hash[attr] = val
       end
     end
   end
 
   self.initvars
 
-  # Define one or more binaries we'll be using.  If a block is passed, yield the name
-  # and path to the block (really only used by 'commands').
-  #
-  # (see #commands)
-  def self.optional_commands(hash)
-    hash.each do |name, target|
-      name = symbolize(name)
-      command = target.is_a?(String) ? Puppet::Provider::Command.new(target) : target
-
-      @commands[name] = command.executable
-
-      yield(name, command.executable) if block_given?
-
-      # Now define the class and instance methods.
-      create_class_and_instance_method(name) do |*args|
-        return command.execute(name, Puppet::Util, Puppet::Util::Execution, *args)
-      end
-    end
-  end
-
   def self.create_class_and_instance_method(name, &block)
     unless singleton_class.method_defined?(name)
       meta_def(name, &block)
     end
 
     unless method_defined?(name)
       define_method(name) do |*args|
         self.class.send(name, *args)
       end
     end
   end
   private_class_method :create_class_and_instance_method
 
   # Retrieve the data source.  Defaults to the provider name.
   def self.source
     @source ||= self.name
   end
 
   # Does this provider support the specified parameter?
   def self.supports_parameter?(param)
     if param.is_a?(Class)
       klass = param
     else
       unless klass = resource_type.attrclass(param)
         raise Puppet::DevError, "'#{param}' is not a valid parameter for #{resource_type.name}"
       end
     end
     return true unless features = klass.required_features
 
     !!satisfies?(*features)
   end
 
 #    def self.to_s
 #        unless defined?(@str)
 #            if self.resource_type
 #                @str = "#{resource_type.name} provider #{self.name}"
 #            else
 #                @str = "unattached provider #{self.name}"
 #            end
 #        end
 #        @str
 #    end
 
   dochook(:defaults) do
     if @defaults.length > 0
       return "Default for " + @defaults.collect do |f, v|
         "`#{f}` == `#{[v].flatten.join(', ')}`"
       end.join(" and ") + "."
     end
   end
 
   dochook(:commands) do
     if @commands.length > 0
       return "Required binaries: " + @commands.collect do |n, c|
         "`#{c}`"
       end.join(", ") + "."
     end
   end
 
   dochook(:features) do
     if features.length > 0
       return "Supported features: " + features.collect do |f|
         "`#{f}`"
       end.join(", ") + "."
     end
   end
 
   # Remove the reference to the resource, so GC can clean up.
   def clear
     @resource = nil
     @model = nil
   end
 
   # Retrieve a named command.
   def command(name)
     self.class.command(name)
   end
 
   # Get a parameter value.
   def get(param)
     @property_hash[symbolize(param)] || :absent
   end
 
   def initialize(resource = nil)
     if resource.is_a?(Hash)
       # We don't use a duplicate here, because some providers (ParsedFile, at least)
       # use the hash here for later events.
       @property_hash = resource
     elsif resource
       @resource = resource
       # LAK 2007-05-09: Keep the model stuff around for backward compatibility
       @model = resource
       @property_hash = {}
     else
       @property_hash = {}
     end
   end
 
   def name
     if n = @property_hash[:name]
       return n
     elsif self.resource
       resource.name
     else
       raise Puppet::DevError, "No resource and no name in property hash in #{self.class.name} instance"
     end
   end
 
   # Set passed params as the current values.
   def set(params)
     params.each do |param, value|
       @property_hash[symbolize(param)] = value
     end
   end
 
   def to_s
     "#{@resource}(provider=#{self.class.name})"
   end
 
   # Make providers comparable.
   include Comparable
   def <=>(other)
     # We can only have ordering against other providers.
     return nil unless other.is_a? Puppet::Provider
     # Otherwise, order by the providers class name.
     return self.class.name <=> other.class.name
   end
 end
 
diff --git a/lib/puppet/provider/package/macports.rb b/lib/puppet/provider/package/macports.rb
index 43e26d130..339a5775a 100755
--- a/lib/puppet/provider/package/macports.rb
+++ b/lib/puppet/provider/package/macports.rb
@@ -1,104 +1,107 @@
 require 'puppet/provider/package'
 require 'puppet/provider/command'
 
 Puppet::Type.type(:package).provide :macports, :parent => Puppet::Provider::Package do
   desc "Package management using MacPorts on OS X.
 
     Supports MacPorts versions and revisions, but not variants.
     Variant preferences may be specified using
     [the MacPorts variants.conf file](http://guide.macports.org/chunked/internals.configuration-files.html#internals.configuration-files.variants-conf).
 
     When specifying a version in the Puppet DSL, only specify the version, not the revision.
     Revisions are only used internally for ensuring the latest version/revision of a port.
   "
 
   confine :operatingsystem => :darwin
-  commands :port => Puppet::Provider::Command.new("/opt/local/bin/port", { :custom_environment => { :HOME => ENV['HOME'] } })
+
+  has_command(:port, "/opt/local/bin/port") do 
+    environment :HOME => "/opt/local"
+  end
 
   has_feature :installable
   has_feature :uninstallable
   has_feature :upgradeable
   has_feature :versionable
 
 
   def self.parse_installed_query_line(line)
     regex = /(\S+)\s+@(\S+)_(\d+).*\(active\)/
     fields = [:name, :ensure, :revision]
     hash_from_line(line, regex, fields)
   end
 
   def self.parse_info_query_line(line)
     regex = /(\S+)\s+(\S+)/
     fields = [:version, :revision]
     hash_from_line(line, regex, fields)
   end
 
   def self.hash_from_line(line, regex, fields)
     hash = {}
     if match = regex.match(line)
       fields.zip(match.captures) { |field, value|
         hash[field] = value
       }
       hash[:provider] = self.name
       return hash
     end
     nil
   end
 
   def self.instances
     packages = []
     port("-q", :installed).each_line do |line|
       if hash = parse_installed_query_line(line)
         packages << new(hash)
       end
     end
     packages
   end
 
   def install
     should = @resource.should(:ensure)
     if [:latest, :installed, :present].include?(should)
       output = port("-q", :install, @resource[:name])
     else
       output = port("-q", :install, @resource[:name], "@#{should}")
     end
     # MacPorts now correctly exits non-zero with appropriate errors in
     # situations where a port cannot be found or installed.
   end
 
   def query
     result = self.class.parse_installed_query_line(execute([command(:port), "-q", :installed, @resource[:name]], :combine => false))
     return {} if result.nil?
     return result
   end
 
   def latest
     # We need both the version and the revision to be confident
     # we've got the latest revision of a specific version
     # Note we're still not doing anything with variants here.
     info_line = execute([command(:port), "-q", :info, "--line", "--version", "--revision", @resource[:name]], :combine => false)
     return nil if info_line == ""
 
     if newest = self.class.parse_info_query_line(info_line)
       current = query
       # We're doing some fiddling behind the scenes here to cope with updated revisions.
       # If we're already at the latest version/revision, then just return the version
       # so the current and desired values match. Otherwise return version and revision
       # to trigger an upgrade to the latest revision.
       if newest[:version] == current[:ensure] and newest[:revision] == current[:revision]
         return current[:ensure]
       else
         return "#{newest[:version]}_#{newest[:revision]}"
       end
     end
     nil
   end
 
   def uninstall
     port("-q", :uninstall, @resource[:name])
   end
 
   def update
     install
   end
 end
diff --git a/spec/unit/provider/package/pacman_spec.rb b/spec/unit/provider/package/pacman_spec.rb
index f81d163f0..a37fe5b19 100755
--- a/spec/unit/provider/package/pacman_spec.rb
+++ b/spec/unit/provider/package/pacman_spec.rb
@@ -1,266 +1,266 @@
 #!/usr/bin/env rspec
 require 'spec_helper'
 require 'stringio'
 
 provider = Puppet::Type.type(:package).provider(:pacman)
 
 describe provider do
-  let(:no_extra_options) { {} }
+  let(:no_extra_options) { { :custom_environment => {} } }
   let(:executor) { Puppet::Util::Execution }
   let(:resolver) { Puppet::Util }
 
   before do
     resolver.stubs(:which).with('/usr/bin/pacman').returns('/usr/bin/pacman')
     provider.stubs(:which).with('/usr/bin/pacman').returns('/usr/bin/pacman')
     @resource = Puppet::Type.type(:package).new(:name => 'package')
     @provider = provider.new(@resource)
   end
 
   describe "when installing" do
     before do
       @provider.stubs(:query).returns({
         :ensure => '1.0'
       })
     end
 
     it "should call pacman to install the right package quietly" do
       executor.
         expects(:execute).
         at_least_once.
         with(["/usr/bin/pacman", "--noconfirm", "--noprogressbar", "-Sy", @resource[:name]], no_extra_options).
         returns ""
 
       @provider.install
     end
 
     it "should raise an ExecutionFailure if the installation failed" do
       executor.stubs(:execute).returns("")
       @provider.expects(:query).returns(nil)
 
       lambda { @provider.install }.should raise_exception(Puppet::ExecutionFailure)
     end
 
     context "when :source is specified" do
       before :each do
         @install = sequence("install")
       end
 
       context "recognizable by pacman" do
         %w{
           /some/package/file
           http://some.package.in/the/air
           ftp://some.package.in/the/air
         }.each do |source|
           it "should install #{source} directly" do
             @resource[:source] = source
 
             executor.expects(:execute).
               with(all_of(includes("-Sy"), includes("--noprogressbar")), no_extra_options).
               in_sequence(@install).
               returns("")
 
             executor.expects(:execute).
               with(all_of(includes("-U"), includes(source)), no_extra_options).
               in_sequence(@install).
               returns("")
 
             @provider.install
           end
         end
       end
 
       context "as a file:// URL" do
         before do
           @package_file = "file:///some/package/file"
           @actual_file_path = "/some/package/file"
           @resource[:source] = @package_file
         end
 
         it "should install from the path segment of the URL" do
           executor.expects(:execute).
             with(all_of(includes("-Sy"),
                         includes("--noprogressbar"),
                         includes("--noconfirm")),
                  no_extra_options).
             in_sequence(@install).
             returns("")
 
           executor.expects(:execute).
             with(all_of(includes("-U"), includes(@actual_file_path)), no_extra_options).
             in_sequence(@install).
             returns("")
 
           @provider.install
         end
       end
 
       context "as a puppet URL" do
         before do
           @resource[:source] = "puppet://server/whatever"
         end
 
         it "should fail" do
           lambda { @provider.install }.should raise_error(Puppet::Error)
         end
       end
 
       context "as a malformed URL" do
         before do
           @resource[:source] = "blah://"
         end
 
         it "should fail" do
           lambda { @provider.install }.should raise_error(Puppet::Error)
         end
       end
     end
   end
 
   describe "when updating" do
     it "should call install" do
       @provider.expects(:install).returns("install return value")
       @provider.update.should == "install return value"
     end
   end
 
   describe "when uninstalling" do
     it "should call pacman to remove the right package quietly" do
       executor.
         expects(:execute).
         with(["/usr/bin/pacman", "--noconfirm", "--noprogressbar", "-R", @resource[:name]], no_extra_options).
         returns ""
 
       @provider.uninstall
     end
   end
 
   describe "when querying" do
     it "should query pacman" do
       executor.
         expects(:execute).
         with(["/usr/bin/pacman", "-Qi", @resource[:name]], no_extra_options)
       @provider.query
     end
 
     it "should return the version" do
       query_output = <<EOF
 Name           : package
 Version        : 1.01.3-2
 URL            : http://www.archlinux.org/pacman/
 Licenses       : GPL
 Groups         : base
 Provides       : None
 Depends On     : bash  libarchive>=2.7.1  libfetch>=2.25  pacman-mirrorlist
 Optional Deps  : fakeroot: for makepkg usage as normal user
                  curl: for rankmirrors usage
 Required By    : None
 Conflicts With : None
 Replaces       : None
 Installed Size : 2352.00 K
 Packager       : Dan McGee <dan@archlinux.org>
 Architecture   : i686
 Build Date     : Sat 22 Jan 2011 03:56:41 PM EST
 Install Date   : Thu 27 Jan 2011 06:45:49 AM EST
 Install Reason : Explicitly installed
 Install Script : Yes
 Description    : A library-based package manager with dependency support
 EOF
 
       executor.expects(:execute).returns(query_output)
       @provider.query.should == {:ensure => "1.01.3-2"}
     end
 
     it "should return a nil if the package isn't found" do
       executor.expects(:execute).returns("")
       @provider.query.should be_nil
     end
 
     it "should return a hash indicating that the package is missing on error" do
       executor.expects(:execute).raises(Puppet::ExecutionFailure.new("ERROR!"))
       @provider.query.should == {
         :ensure => :purged,
         :status => 'missing',
         :name => @resource[:name],
         :error => 'ok',
       }
     end
   end
 
   describe "when fetching a package list" do
     it "should query pacman" do
       provider.expects(:execpipe).with(["/usr/bin/pacman", '-Q'])
       provider.instances
     end
 
     it "should return installed packages with their versions" do
       provider.expects(:execpipe).yields(StringIO.new("package1 1.23-4\npackage2 2.00\n"))
       packages = provider.instances
 
       packages.length.should == 2
 
       packages[0].properties.should == {
         :provider => :pacman,
         :ensure => '1.23-4',
         :name => 'package1'
       }
 
       packages[1].properties.should == {
         :provider => :pacman,
         :ensure => '2.00',
         :name => 'package2'
       }
     end
 
     it "should return nil on error" do
       provider.expects(:execpipe).raises(Puppet::ExecutionFailure.new("ERROR!"))
       provider.instances.should be_nil
     end
 
     it "should warn on invalid input" do
       provider.expects(:execpipe).yields(StringIO.new("blah"))
       provider.expects(:warning).with("Failed to match line blah")
       provider.instances.should == []
     end
   end
 
   describe "when determining the latest version" do
     it "should refresh package list" do
       get_latest_version = sequence("get_latest_version")
       executor.
         expects(:execute).
         in_sequence(get_latest_version).
         with(['/usr/bin/pacman', '-Sy'], no_extra_options)
 
       executor.
         stubs(:execute).
         in_sequence(get_latest_version).
         returns("")
 
       @provider.latest
     end
 
     it "should get query pacman for the latest version" do
       get_latest_version = sequence("get_latest_version")
       executor.
         stubs(:execute).
         in_sequence(get_latest_version)
 
       executor.
         expects(:execute).
         in_sequence(get_latest_version).
         with(['/usr/bin/pacman', '-Sp', '--print-format', '%v', @resource[:name]], no_extra_options).
         returns("")
 
       @provider.latest
     end
 
     it "should return the version number from pacman" do
       executor.
         expects(:execute).
         at_least_once().
         returns("1.00.2-3\n")
 
       @provider.latest.should == "1.00.2-3"
     end
   end
 end
diff --git a/spec/unit/provider_spec.rb b/spec/unit/provider_spec.rb
index 114daffa8..9f697725b 100755
--- a/spec/unit/provider_spec.rb
+++ b/spec/unit/provider_spec.rb
@@ -1,155 +1,212 @@
 require 'spec_helper'
 
 describe Puppet::Provider do
   after do
     Puppet::Type.rmtype(:dummy)
   end
 
-  describe "required commands" do
-    it "installs to run executables by path" do
+  describe "has command" do
+    it "installs a method to run the command specified by the path" do
+      echo_command = expect_command_executed(:echo, "/bin/echo", "an argument")
+      allow_creation_of(echo_command)
+
+      provider = provider_of do
+        has_command(:echo, "/bin/echo")
+      end
+
+      provider.echo("an argument")
+    end
+
+    it "installs a command that is run with a given environment" do
+      echo_command = expect_command_executed(:echo, "/bin/echo", "an argument")
+      allow_creation_of(echo_command, {
+        :EV => "value",
+        :OTHER => "different"
+      })
+
+      provider = provider_of do
+        has_command(:echo, "/bin/echo") do
+          environment :EV => "value", :OTHER => "different"
+        end
+      end
+
+      provider.echo("an argument")
+    end
+
+    it "is required by default" do
+      provider = provider_of do
+        has_command(:does_not_exist, "/does/not/exist")
+      end
+
+      provider.should_not be_suitable
+    end
+
+    it "is required by default" do
+      provider = provider_of do
+        has_command(:does_exist, "/exists/somewhere")
+      end
+
+      file_exists_and_is_executable("/exists/somewhere")
+
+      provider.should be_suitable
+    end
+
+    it "can be specified as optional" do
+      provider = provider_of do
+        has_command(:does_not_exist, "/does/not/exist") do
+          is_optional
+        end
+      end
+
+      provider.should be_suitable
+    end
+  end
+
+  describe "has required commands" do
+    it "installs methods to run executables by path" do
       echo_command = expect_command_executed(:echo, "/bin/echo", "an argument")
       ls_command = expect_command_executed(:ls, "/bin/ls")
 
       allow_creation_of(echo_command)
       allow_creation_of(ls_command)
 
       provider = provider_of do
         commands :echo => "/bin/echo", :ls => "/bin/ls"
       end
 
       provider.echo("an argument")
       provider.ls
     end
 
     it "allows the provider to be suitable if the executable is present" do
       provider = provider_of do
         commands :always_exists => "/this/command/exists"
       end
 
       file_exists_and_is_executable("/this/command/exists")
 
       provider.should be_suitable
     end
 
     it "does not allow the provider to be suitable if the executable is not present" do
       provider = provider_of do
         commands :does_not_exist => "/this/command/does/not/exist"
       end
 
       provider.should_not be_suitable
     end
   end
 
-  describe "optional commands" do
+  describe "has optional commands" do
     it "installs methods to run executables" do
       echo_command = expect_command_executed(:echo, "/bin/echo", "an argument")
       ls_command = expect_command_executed(:ls, "/bin/ls")
 
       allow_creation_of(echo_command)
       allow_creation_of(ls_command)
 
       provider = provider_of do
         optional_commands :echo => "/bin/echo", :ls => "/bin/ls"
       end
 
       provider.echo("an argument")
       provider.ls
     end
 
     it "allows the provider to be suitable even if the executable is not present" do
       provider = provider_of do
         optional_commands :does_not_exist => "/this/command/does/not/exist"
       end
 
       provider.should be_suitable
     end
   end
 
   it "makes command methods on demand (deprecated)" do
     Puppet::Util.expects(:which).with("/not/a/command").returns("/not/a/command")
     Puppet::Util::Execution.expects(:execute).with(["/not/a/command"], {})
 
     provider = provider_of do
       @commands[:echo] = "/not/a/command"
     end
     provider.stubs(:which).with("/not/a/command").returns("/not/a/command")
 
     provider.make_command_methods(:echo)
     provider.echo
   end
 
   it "should consider two defaults to be higher specificity than one default" do
     one = provider_of do
       defaultfor :operatingsystem => "solaris"
     end
 
     two = provider_of do
       defaultfor :operatingsystem => "solaris", :operatingsystemrelease => "5.10"
     end
 
     two.specificity.should > one.specificity
   end
 
   it "should consider a subclass more specific than its parent class" do
     one = provider_of {}
 
     two = provider_of({ :parent => one }) {}
 
     two.specificity.should > one.specificity
   end
 
   it "should be Comparable" do
     res = Puppet::Type.type(:notify).new(:name => "res")
 
     # Normally I wouldn't like the stubs, but the only way to name a class
     # otherwise is to assign it to a constant, and that hurts more here in
     # testing world. --daniel 2012-01-29
     a = Class.new(Puppet::Provider).new(res)
     a.class.stubs(:name).returns "Puppet::Provider::Notify::A"
 
     b = Class.new(Puppet::Provider).new(res)
     b.class.stubs(:name).returns "Puppet::Provider::Notify::B"
 
     c = Class.new(Puppet::Provider).new(res)
     c.class.stubs(:name).returns "Puppet::Provider::Notify::C"
 
     [[a, b, c], [a, c, b], [b, a, c], [b, c, a], [c, a, b], [c, b, a]].each do |this|
       this.sort.should == [a, b, c]
     end
 
     a.should be < b
     a.should be < c
     b.should be > a
     b.should be < c
     c.should be > a
     c.should be > b
 
     [a, b, c].each {|x| a.should be <= x }
     [a, b, c].each {|x| c.should be >= x }
 
     b.should be_between(a, c)
   end
 
   def provider_of(options = {}, &block) 
     type = Puppet::Type.newtype(:dummy) do
       provide(:dummy, options, &block)
     end
 
     type.provider(:dummy)
   end
 
   def expect_command_executed(name, path, *args) 
     command = Puppet::Provider::Command.new(path)
     command.expects(:execute).with(name, Puppet::Util, Puppet::Util::Execution, *args)
     command
   end
 
-  def allow_creation_of(command)
-    Puppet::Provider::Command.stubs(:new).with(command.executable).returns(command)
+  def allow_creation_of(command, environment = {})
+      Puppet::Provider::Command.stubs(:new).with(command.executable, { :custom_environment => environment }).returns(command)
   end
 
   def file_exists_and_is_executable(path) 
     FileTest.expects(:file?).with(path).returns(true)
     FileTest.expects(:executable?).with(path).returns(true)
   end
 end