fix bug when using passed in project_dir when using the API directly

Gemfile

@@ -1,2 +1,4 @@
 source 'https://rubygems.org'
 gemspec
+
+gem 'pry'

lib/librarian/puppet/dsl.rb

@@ -42,7 +42,7 @@ class Receiver < Librarian::Dsl::Receiver
 
         # save the specfile and call librarian
         def run(specfile = nil)
-          @working_path = specfile.kind_of?(Pathname) ? specfile.parent : Pathname.new(Dir.pwd)
+          @working_path = specfile.path.kind_of?(Pathname) ? specfile.path.parent : (Dir.pwd)
           @specfile = specfile
           super
         end

spec/receiver_spec.rb

@@ -0,0 +1,20 @@
+require 'spec_helper'
+
+describe 'Librarian::Puppet::Receiver' do
+
+  describe '#run' do
+
+    it 'working_dir from pwd' do
+      rec = Librarian::Puppet::Receiver.new(target)
+      rec.run(nil)
+      expect(rec.working_dir).to eq(Dir.pwd)
+    end
+
+    it 'working_dir from given path' do
+      rec = Librarian::Puppet::Receiver.new(target)
+      specfile = Pathname.new('/tmp/tmp_module/Puppetfile')
+      rec.run(specfile)
+      expect(rec.working_dir).to eq('/tmp/tmp_module')
+    end
+  end
+end