Add support of empty device lists fixes #37

Author: TDesjardins

src/main/java/com/github/kaklakariada/fritzbox/model/homeautomation/DeviceList.java

@@ -19,6 +19,7 @@
 
 import static java.util.stream.Collectors.toList;
 
+import java.util.ArrayList;
 import java.util.List;
 
 import org.simpleframework.xml.Attribute;
@@ -31,8 +32,8 @@ public class DeviceList {
     @Attribute(name = "version")
     private String apiVersion;
 
-    @ElementList(name = "device", type = Device.class, inline = true)
-    private List<Device> devices;
+    @ElementList(name = "device", type = Device.class, inline = true, required = false)
+    private List<Device> devices = new ArrayList<>();
 
     @ElementList(name = "group", type = Group.class, inline = true, required = false)
     private List<Group> groups;

src/test/java/com/github/kaklakariada/fritzbox/mapping/DeserializerTest.java

@@ -90,6 +90,12 @@ void parseDeviceListAllTogether() throws IOException {
         assertThat(deviceList.getDevices()).hasSize(5);
     }
 
+    @Test
+    void parseDeviceListEmpty() throws IOException {
+        final DeviceList deviceList = parseDeviceList(Paths.get("src/test/resources/FritzOS29/deviceListEmpty.xml"));
+        assertThat(deviceList.getDevices()).hasSize(0);
+    }
+
     @Test
     void parseDeviceList() throws IOException {
         final DeviceList deviceList = parseDeviceList(Paths.get("src/test/resources/deviceList.xml"));

src/test/resources/FritzOS29/deviceListEmpty.xml

@@ -0,0 +1 @@
+<devicelist version="1" fwversion="7.29"></devicelist>