Make export dir cleanliness checking more granular

ExportRepo now only fails if there are files in cookbooks/ or
data_bags/policyfiles/. Fixes an issue where export would not work with
test kitchen when other kitchen directories were created first.

lib/chef-dk/policyfile_services/export_repo.rb

@@ -57,7 +57,7 @@ def policy_name
 
       def run
         assert_lockfile_exists!
-        assert_export_dir_empty!
+        assert_export_dir_clean!
 
         validate_lockfile
         write_updated_lockfile
@@ -86,10 +86,12 @@ def export
       private
 
       def create_repo_structure
-        FileUtils.rm_rf(export_dir)
+        FileUtils.rm_rf(cookbooks_dir)
+        FileUtils.rm_rf(policyfiles_data_bag_dir)
+
         FileUtils.mkdir_p(export_dir)
-        FileUtils.mkdir_p(File.join(export_dir, "cookbooks"))
-        FileUtils.mkdir_p(File.join(export_dir, "data_bags", "policyfiles"))
+        FileUtils.mkdir_p(cookbooks_dir)
+        FileUtils.mkdir_p(policyfiles_data_bag_dir)
       end
 
       def copy_cookbooks
@@ -161,17 +163,30 @@ def assert_lockfile_exists!
         end
       end
 
-      def assert_export_dir_empty!
-        entries = Dir.glob(File.join(export_dir, "*"))
-        if !force_export? && !entries.empty?
-          raise ExportDirNotEmpty, "Export dir (#{export_dir}) not empty. Refusing to export."
+      def assert_export_dir_clean!
+        if !force_export? && !conflicting_fs_entries.empty?
+          msg = "Export dir (#{export_dir}) not clean. Refusing to export. (Conflicting files: #{conflicting_fs_entries.join(', ')})"
+          raise ExportDirNotEmpty, msg
         end
       end
 
       def force_export?
         @force_export
       end
 
+      def conflicting_fs_entries
+        Dir.glob(File.join(cookbooks_dir, "*")) +
+          Dir.glob(File.join(policyfiles_data_bag_dir, "*"))
+      end
+
+      def cookbooks_dir
+        File.join(export_dir, "cookbooks")
+      end
+
+      def policyfiles_data_bag_dir
+        File.join(export_dir, "data_bags", "policyfiles")
+      end
+
     end
 
   end

lib/kitchen/provisioner/policyfile_zero.rb

@@ -119,8 +119,7 @@ def prepare_cookbooks
       #
       # @api private
       def policy_exporter
-        return @policy_exporter if @policy_exporter
-        @policy_exporter = ChefDK::PolicyfileServices::ExportRepo.new(export_dir: sandbox_path)
+        @policy_exporter ||= ChefDK::PolicyfileServices::ExportRepo.new(export_dir: sandbox_path)
       end
 
       # Writes a fake (but valid) validation.pem into the sandbox directory.

spec/unit/policyfile_services/export_repo_spec.rb

@@ -235,21 +235,59 @@
 
         end
 
-        context "When the export dir is already populated" do
+        context "When the export dir has non-conflicting content" do
 
           let(:file_in_export_dir) { File.join(export_dir, "some_random_cruft") }
 
+          let(:extra_data_bag_dir) { File.join(export_dir, "data_bags", "extraneous") }
+
+          let(:extra_data_bag_item) { File.join(extra_data_bag_dir, "an_item.json") }
+
           before do
             FileUtils.mkdir_p(export_dir)
             File.open(file_in_export_dir, "wb+") { |f| f.print "some random cruft" }
+            FileUtils.mkdir_p(extra_data_bag_dir)
+            File.open(extra_data_bag_item, "wb+") { |f| f.print "some random cruft" }
+          end
+
+          it "ignores the non-conflicting content and exports" do
+            export_service.run
+
+            expect(File).to exist(file_in_export_dir)
+            expect(File).to exist(extra_data_bag_item)
+
+            expect(File).to be_directory(File.join(export_dir, "cookbooks"))
+            expect(File).to be_directory(File.join(export_dir, "data_bags"))
+          end
+        end
+
+        context "When the export dir has conflicting content" do
+
+          let(:non_conflicting_file_in_export_dir) { File.join(export_dir, "some_random_cruft") }
+
+          let(:cookbooks_dir) { File.join(export_dir, "cookbooks") }
+
+          let(:file_in_cookbooks_dir) { File.join(cookbooks_dir, "some_random_cruft") }
+
+          let(:policyfiles_data_bag_dir) { File.join(export_dir, "data_bags", "policyfiles") }
+
+          let(:extra_policyfile_data_item) { File.join(policyfiles_data_bag_dir, "leftover-policy.json") }
+
+          before do
+            FileUtils.mkdir_p(export_dir)
+            FileUtils.mkdir_p(cookbooks_dir)
+            FileUtils.mkdir_p(policyfiles_data_bag_dir)
+            File.open(non_conflicting_file_in_export_dir, "wb+") { |f| f.print "some random cruft" }
+            File.open(file_in_cookbooks_dir, "wb+") { |f| f.print "some random cruft" }
+            File.open(extra_policyfile_data_item, "wb+") { |f| f.print "some random cruft" }
           end
 
           it "raises a PolicyfileExportRepoError" do
-            message = "Export dir (#{export_dir}) not empty. Refusing to export."
+            message = "Export dir (#{export_dir}) not clean. Refusing to export. (Conflicting files: #{file_in_cookbooks_dir}, #{extra_policyfile_data_item})"
             expect { export_service.run }.to raise_error(ChefDK::ExportDirNotEmpty, message)
-            expect(File).to be_file(file_in_export_dir)
-            expect(File).to_not exist(File.join(export_dir, "cookbooks"))
-            expect(File).to_not exist(File.join(export_dir, "data_bags"))
+            expect(File).to exist(non_conflicting_file_in_export_dir)
+            expect(File).to exist(file_in_cookbooks_dir)
+            expect(File).to exist(extra_policyfile_data_item)
           end
 
           context "and the force option is set" do
@@ -259,7 +297,11 @@
             it "clears the export dir and exports" do
               export_service.run
 
-              expect(File).to_not exist(file_in_export_dir)
+              expect(File).to_not exist(file_in_cookbooks_dir)
+              expect(File).to_not exist(extra_policyfile_data_item)
+
+              expect(File).to exist(non_conflicting_file_in_export_dir)
+
               expect(File).to be_directory(File.join(export_dir, "cookbooks"))
               expect(File).to be_directory(File.join(export_dir, "data_bags"))
             end