diff --git a/library/network/src/lib/y2firewall/firewalld/interface.rb b/library/network/src/lib/y2firewall/firewalld/interface.rb
index 629b1798c..20031e2cd 100644
--- a/library/network/src/lib/y2firewall/firewalld/interface.rb
+++ b/library/network/src/lib/y2firewall/firewalld/interface.rb
@@ -21,6 +21,7 @@
 
 require "yast"
 require "y2firewall/firewalld"
+Yast.import "NetworkInterfaces"
 
 module Y2Firewall
   class Firewalld
@@ -33,8 +34,6 @@ class Interface
       #
       # @param name [String] interface name
       def initialize(name)
-        Yast.import "NetworkInterfaces"
-
         @id = name.to_sym
       end
 
@@ -42,9 +41,7 @@ def initialize(name)
       #
       # @return [Array<Y2Firewall::Firewalld::Interface>] known interfaces
       def self.known
-        Yast.import "NetworkInterfaces"
         interfaces = Yast::NetworkInterfaces.List("").reject { |i| i == "lo" }
-
         interfaces.map { |i| new(i) }
       end
 
diff --git a/library/network/test/y2firewall/firewalld/interface_test.rb b/library/network/test/y2firewall/firewalld/interface_test.rb
new file mode 100644
index 000000000..a931cd34a
--- /dev/null
+++ b/library/network/test/y2firewall/firewalld/interface_test.rb
@@ -0,0 +1,86 @@
+#!/usr/bin/env rspec
+# encoding: utf-8
+
+# Copyright (c) [2018] SUSE LLC
+#
+# All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of version 2 of the GNU General Public License as published
+# by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+# more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, contact SUSE LLC.
+#
+# To contact SUSE LLC about this file by physical or electronic mail, you may
+# find current contact information at www.suse.com.
+
+require_relative "../../test_helper"
+require "y2firewall/firewalld/interface"
+
+describe Y2Firewall::Firewalld::Interface do
+  subject(:iface) { described_class.new("eth0") }
+
+  describe ".known" do
+    before do
+      allow(Yast::NetworkInterfaces).to receive(:List).with("")
+        .and_return(["eth0", "lo", "wlan0"])
+    end
+
+    it "returns an object for each known interface except 'lo'" do
+      expect(described_class.known).to contain_exactly(
+        an_object_having_attributes(name: "eth0"),
+        an_object_having_attributes(name: "wlan0")
+      )
+    end
+  end
+
+  describe "#name" do
+    it "returns the interface name" do
+      expect(iface.name).to eq("eth0")
+    end
+  end
+
+  describe "#id" do
+    it "returns the name as a symbol" do
+      expect(iface.id).to eq(:eth0)
+    end
+  end
+
+  describe "#device_name" do
+    DEVICE_NAME = "Some Device Name".freeze
+
+    before do
+      allow(Yast::NetworkInterfaces).to receive(:GetValue).with("eth0", "NAME")
+        .and_return(DEVICE_NAME)
+    end
+
+    it "returns the device name" do
+      expect(iface.device_name).to eq(DEVICE_NAME)
+    end
+  end
+
+  describe "#zone" do
+    let(:public_zone) do
+      instance_double(Y2Firewall::Firewalld::Zone, interfaces: ["eth1"])
+    end
+
+    let(:dmz_zone) do
+      instance_double(Y2Firewall::Firewalld::Zone, interfaces: ["eth0"])
+    end
+
+    before do
+      allow(Y2Firewall::Firewalld.instance).to receive(:zones)
+        .and_return([public_zone, dmz_zone])
+    end
+
+    it "returns the zone where the interface belongs to" do
+      expect(iface.zone).to eq(dmz_zone)
+    end
+  end
+end