Add unit test for unplugged interfaces

src/lib/y2network/interface_config_builder.rb

@@ -129,7 +129,7 @@ def save
       yast_config.add_or_update_connection_config(@connection_config)
       # Assign the new added interface in case of a new connection for an
       # unplugged one (bsc#1162679)
-      interface ||= find_interface
+      self.interface = find_interface unless interface
 
       if interface.respond_to?(:custom_driver)
         interface.custom_driver = driver_auto? ? nil : driver.name

test/y2network/interface_config_builder_test.rb

@@ -110,6 +110,19 @@
       subject.save
     end
 
+    context "when the new connection config is for an unplugged interface" do
+      subject(:config_builder) do
+        res = Y2Network::InterfaceConfigBuilder.for("eth")
+        res.name = "eth1"
+        res
+      end
+
+      it "assigns the added interface to the builder" do
+        subject.save
+        expect(subject.interface.name).to eq("eth1")
+      end
+    end
+
     context "when interface was renamed" do
       before do
         subject.rename_interface("eth2")