diff --git a/lib/http/http_client.dart b/lib/http/http_client.dart
index 6d0b0e1..58f9041 100644
--- a/lib/http/http_client.dart
+++ b/lib/http/http_client.dart
@@ -110,7 +110,7 @@ class HttpClient implements Http {
         }
       }
 
-      return Response(res, json!);
+      return Response(res, json ?? jsonDecode('{}'));
     });
   }
 
diff --git a/lib/models/week_model.dart b/lib/models/week_model.dart
index 739b31c..6ed4561 100644
--- a/lib/models/week_model.dart
+++ b/lib/models/week_model.dart
@@ -10,13 +10,13 @@ class WeekModel extends WeekBaseModel implements Model {
     PictogramModel? thumbnail,
     String? name,
     List<WeekdayModel>? days,
-    this.weekYear,
-    this.weekNumber,
+    this.weekYear = 0,
+    this.weekNumber = 0,
   }) : super(thumbnail: thumbnail, name: name, days: days);
 
   /// Construct from JSON
-  WeekModel.fromJson(Map<String, dynamic>? json) : super.fromJson(json) {
-    weekYear = json!['weekYear'];
+  WeekModel.fromJson(Map<String, dynamic> json) : super.fromJson(json) {
+    weekYear = json['weekYear'];
     weekNumber = json['weekNumber'];
   }
 
@@ -27,10 +27,13 @@ class WeekModel extends WeekBaseModel implements Model {
   }
 
   /// The year the week lies in
-  int? weekYear;
+  int weekYear = DateTime.now().year;
 
   /// The week number
-  int? weekNumber;
+  int weekNumber =
+      DateTime.now().difference(DateTime(DateTime.now().year, 1, 1)).inDays ~/
+              7 +
+          1;
 
   @override
   Map<String, dynamic> toJson() {
diff --git a/test/api/activity_api_test.dart b/test/api/activity_api_test.dart
index 63b40c0..26e4067 100644
--- a/test/api/activity_api_test.dart
+++ b/test/api/activity_api_test.dart
@@ -66,8 +66,8 @@ Future<void> main() async {
 
   test('Should add an activity', () {
     activityApi
-        .add(mockActivity, mockUser.id!, mockWeek.name!, mockWeek.weekYear!,
-            mockWeek.weekNumber!, mockWeek.days!.first.day!)
+        .add(mockActivity, mockUser.id!, mockWeek.name!, mockWeek.weekYear,
+            mockWeek.weekNumber, mockWeek.days!.first.day!)
         .listen(expectAsync1((ActivityModel response) {
       expect(response.toJson(), mockActivity.toJson());
     }));
diff --git a/test/api/week_api_test.dart b/test/api/week_api_test.dart
index 288c78e..bad6282 100644
--- a/test/api/week_api_test.dart
+++ b/test/api/week_api_test.dart
@@ -72,7 +72,7 @@ Future<void> main() async {
     );
 
     weekApi
-        .get(id, week.weekYear!, week.weekNumber!)
+        .get(id, week.weekYear, week.weekNumber)
         .listen(expectAsync1((WeekModel resWeek) {
       expect(resWeek.toJson(), week.toJson());
     }));
@@ -106,7 +106,7 @@ Future<void> main() async {
     );
 
     weekApi
-        .update(id, week.weekYear!, week.weekNumber!, week)
+        .update(id, week.weekYear, week.weekNumber, week)
         .listen(expectAsync1((WeekModel resWeek) {
       expect(resWeek.toJson(), week.toJson());
     }));
diff --git a/test/models/week_model_test.dart b/test/models/week_model_test.dart
index 8378661..276d334 100644
--- a/test/models/week_model_test.dart
+++ b/test/models/week_model_test.dart
@@ -130,10 +130,6 @@ void main() {
     weekBaseTest(week2, response2);
   });
 
-  test('Should throw exception when JSON is null', () {
-    expect(() => WeekModel.fromJson(null), throwsFormatException);
-  });
-
   test('Should be able to serialize to JSON', () {
     final WeekModel week1 = WeekModel.fromJson(response1!);
     final WeekModel week2 = WeekModel.fromJson(response2!);