diff --git a/src/lib/y2network/widgets/s390_common.rb b/src/lib/y2network/widgets/s390_common.rb
index 935e259d6..8944c801f 100644
--- a/src/lib/y2network/widgets/s390_common.rb
+++ b/src/lib/y2network/widgets/s390_common.rb
@@ -247,7 +247,8 @@ def handle(event)
       def validate
         return true if !layer2? || valid_mac?(mac_address_widget.value)
 
-        report_mac_error && false
+        report_mac_error
+        false
       end
 
     private
@@ -258,24 +259,36 @@ def report_mac_error
         Yast::Popup.Error(msg)
       end
 
+      # Convenience method to check whether layer2 support is enabled or not
+      #
+      # @return [Boolean] true if enabled; false otherwise
       def layer2?
         !!support_widget.value
       end
 
+      # Convenience method to check whether the MAC address provided is valid
+      # or not
+      #
+      # @return [Boolean] true when valid; false otherwise
+      # @param mac_address [String]
       def valid_mac?(mac_address)
         return false if mac_address.to_s.empty?
         return false if mac_address == "00:00:00:00:00:00"
         !!(mac_address =~ /^([0-9a-fA-F]{2}[:-]){5}[0-9a-fA-F]{2}$/i)
       end
 
+      # Convenience method to enable or disable the mac address widget when the
+      # layer2 support is modified
       def refresh
         support_widget.checked? ? mac_address_widget.enable : mac_address_widget.disable
       end
 
+      # @return [S390Layer2Support]
       def support_widget
         @support_widget ||= S390Layer2Support.new(@settings)
       end
 
+      # @return [S390Layer2Address]
       def mac_address_widget
         @mac_address_widget ||= S390Layer2Address.new(@settings)
       end
diff --git a/test/y2network/widgets/s390_common_test.rb b/test/y2network/widgets/s390_common_test.rb
index 510afb4e6..0c957b220 100644
--- a/test/y2network/widgets/s390_common_test.rb
+++ b/test/y2network/widgets/s390_common_test.rb
@@ -73,3 +73,87 @@
 
   include_examples "CWM::InputField"
 end
+
+describe Y2Network::Widgets::S390Layer2 do
+  let(:builder) { Y2Network::InterfaceConfigBuilder.for("qeth") }
+  let(:layer2_support) { true }
+  let(:layer2_address) { "00:00:00:00:00:00" }
+  let(:layer2_support_widget) do
+    instance_double("Y2Network::WidgetsS390Layer2Support",
+      value: layer2_support, widget_id: "layer2_support")
+  end
+
+  let(:layer2_address_widget) do
+    instance_double("Y2Network::WidgetsS390Layer2Address",
+      value: layer2_address, widget_id: "layer2_address")
+  end
+
+  subject { described_class.new(builder) }
+
+  before do
+    allow(subject).to receive(:support_widget).and_return(layer2_support_widget)
+    allow(subject).to receive(:mac_address_widget).and_return(layer2_address_widget)
+  end
+
+  include_examples "CWM::CustomWidget"
+
+  describe "#handle" do
+    context "when the event handled is for the layer2_support widget" do
+      it "refresh the mac address widget" do
+        expect(subject).to receive(:refresh)
+        subject.handle("ID" => "layer2_support")
+      end
+    end
+
+    it "returns nil" do
+      allow(subject).to receive(:refresh)
+      expect(subject.handle("ID" => "layer2_address")).to be_nil
+      expect(subject.handle("ID" => "layer2_support")).to be_nil
+    end
+  end
+
+  describe "#validate" do
+    context "when the layer2 support is not enabled" do
+      let(:layer2_support) { false }
+      it "returns true" do
+        expect(subject.validate).to eql(true)
+      end
+    end
+
+    context "when the layer2 support is enabled" do
+      context "and the MAC provided is valid" do
+        let(:layer2_address) { "02:00:00:00:01:FD" }
+
+        it "returns true" do
+          expect(subject.validate).to eql(true)
+        end
+      end
+
+      context "and the MAC address provided is invalid" do
+        it "returns false" do
+          allow(Yast::Popup).to receive(:Error)
+          expect(subject.validate).to eql(false)
+        end
+
+        it "reports an error" do
+          expect(Yast::Popup).to receive(:Error).with(/MAC address provided is not valid/)
+          expect(subject.validate).to eql(false)
+        end
+      end
+    end
+  end
+end
+
+describe Y2Network::Widgets::S390Layer2Support do
+  let(:builder) { Y2Network::InterfaceConfigBuilder.for("qeth") }
+  subject { described_class.new(builder) }
+
+  include_examples "CWM::CheckBox"
+end
+
+describe Y2Network::Widgets::S390Layer2Address do
+  let(:builder) { Y2Network::InterfaceConfigBuilder.for("qeth") }
+  subject { described_class.new(builder) }
+
+  include_examples "CWM::InputField"
+end