WIP: [service] More robust transport and bus checks

service/lib/agama/dbus/storage/interfaces/device/drive.rb

@@ -85,10 +85,10 @@ def drive_model
             #
             # @return [String]
             def drive_bus
-              # FIXME: not sure how robust this is (is the value always in English?)
-              return "" if storage_device.bus.casecmp?("none")
+              # FIXME: not sure whether checking for "none" is robust (is the value always in English?)
+              return "" if storage_device.bus.nil? || storage_device.bus.casecmp?("none")
 
-              storage_device.bus || ""
+              storage_device.bus
             end
 
             # Bus Id for DASD
@@ -114,7 +114,7 @@ def drive_transport
               return "" unless storage_device.respond_to?(:transport)
 
               transport = storage_device.transport
-              return "" if transport.is?(:unknown)
+              return "" if transport.nil? || transport.is?(:unknown)
 
               # FIXME: transport does not have proper i18n support at yast2-storage-ng, so we are
               # just duplicating some logic from yast2-storage-ng here

service/test/agama/dbus/storage/interfaces/device/drive_examples.rb

@@ -192,13 +192,29 @@
         allow(device).to receive(:transport).and_return(transport)
       end
 
-      let(:transport) { instance_double(Y2Storage::DataTransport, to_s: "usb") }
+      let(:transport) { Y2Storage::DataTransport::FCOE }
 
       it "returns the transport" do
-        expect(subject.drive_transport).to eq("usb")
+        expect(subject.drive_transport).to eq("fcoe")
       end
 
-      context "if transport is unknown" do
+      context "if transport is Unknown" do
+        let(:transport) { Y2Storage::DataTransport::UNKNOWN }
+
+        it "returns an empty string" do
+          expect(subject.drive_transport).to eq("")
+        end
+      end
+
+      context "if transport is USB" do
+        let(:transport) { Y2Storage::DataTransport::USB }
+
+        it "returns the corresponding string" do
+          expect(subject.drive_transport).to eq("USB")
+        end
+      end
+
+      context "if transport is missing" do
         let(:transport) { nil }
 
         it "returns an empty string" do