diff --git a/lib/screens/flight_log/flight_log_modal.dart b/lib/screens/flight_log/flight_log_modal.dart
index b1c7d69..365f494 100644
--- a/lib/screens/flight_log/flight_log_modal.dart
+++ b/lib/screens/flight_log/flight_log_modal.dart
@@ -196,7 +196,7 @@ class _FlightLogModalState extends State<FlightLogModal> {
         // fuel + fuel price
         CupertinoFormSection(children: <Widget>[
           CupertinoTextFormFieldRow(
-            key: const Key("flight_log_modal_form_fuel_price"),
+            key: const Key("input_flightLogModal_fuel"),
             controller: _fuelController,
             prefix: Text(AppLocalizations.of(context)!
                 .flightLogModal_label_fuel_cupertino),
@@ -209,6 +209,7 @@ class _FlightLogModalState extends State<FlightLogModal> {
           ),
           // TODO convert to standalone form row widget (using a controller? Though material widget doesn't support it...)
           CupertinoTextFormFieldRow(
+            key: const Key("input_flightLogModal_fuelPrice"),
             controller: _fuelPriceController,
             prefix: Text(AppLocalizations.of(context)!
                 .flightLogModal_label_fuel_cost_cupertino(
@@ -368,7 +369,7 @@ class _FlightLogModalState extends State<FlightLogModal> {
           contentPadding: const EdgeInsets.fromLTRB(20, 5, 20, 5),
           leading: const Icon(Icons.local_gas_station),
           title: TextFormField(
-            key: const Key("flight_log_modal_form_fuel_price"),
+            key: const Key("input_flightLogModal_fuel"),
             controller: _fuelController,
             // TODO cursorColor: widget.model.backgroundColor,
             keyboardType: const TextInputType.numberWithOptions(decimal: true),
@@ -389,6 +390,7 @@ class _FlightLogModalState extends State<FlightLogModal> {
           trailing: SizedBox(
             width: MediaQuery.of(context).size.width * 0.4,
             child: _MaterialFuelPriceSelector.totalCost(
+              key: const Key("input_flightLogModal_fuelPrice"),
               textController: _fuelPriceController,
               currencySymbol: _appConfig.fuelPriceCurrency,
             ),
@@ -442,6 +444,7 @@ class _FlightLogModalState extends State<FlightLogModal> {
       );
       trailingActions = [
         PlatformTextButton(
+          key: const Key('button_flightLogModal_save'),
           onPressed: () => _onSave(context),
           cupertino: (_, __) => CupertinoTextButtonData(
             // workaround for https://github.com/flutter/flutter/issues/32701
@@ -454,6 +457,7 @@ class _FlightLogModalState extends State<FlightLogModal> {
       leadingAction = null;
       trailingActions = [
         PlatformIconButton(
+          key: const Key('button_flightLogModal_save'),
           onPressed: () => _onSave(context),
           icon: const Icon(Icons.check_sharp),
           material: (_, __) => MaterialIconButtonData(
diff --git a/test/screens/flight_log/flight_log_modal_test.dart b/test/screens/flight_log/flight_log_modal_test.dart
index 750d95b..84f223d 100644
--- a/test/screens/flight_log/flight_log_modal_test.dart
+++ b/test/screens/flight_log/flight_log_modal_test.dart
@@ -5,6 +5,7 @@ import 'package:airborne/services/flight_log_services.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 import 'package:flutter_localizations/flutter_localizations.dart';
+import 'package:flutter_platform_widgets/flutter_platform_widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:mockito/annotations.dart';
 import 'package:mockito/mockito.dart';
@@ -13,7 +14,10 @@ import 'package:provider/provider.dart';
 import 'flight_log_modal_test.mocks.dart';
 
 @GenerateMocks([AppConfig, FlightLogBookService])
-void main() {
+void main() async {
+  const locale = Locale('en');
+  final lang = await AppLocalizations.delegate.load(locale);
+
   Widget createSkeletonApp(FlightLogItem model) => MaterialApp(
         localizationsDelegates: const [
           AppLocalizations.delegate,
@@ -21,7 +25,7 @@ void main() {
           GlobalWidgetsLocalizations.delegate,
           GlobalCupertinoLocalizations.delegate,
         ],
-        locale: const Locale('en'),
+        locale: locale,
         home: MultiProvider(
           providers: [
             _provideAppConfigForSampleAircraft(),
@@ -48,39 +52,139 @@ void main() {
       await tester.pumpWidget(createSkeletonApp(item));
 
       await tester.enterText(
-          find.byKey(const Key("flight_log_modal_form_fuel_price")), "42");
+          find.byKey(const Key("input_flightLogModal_fuelPrice")), "42");
       await tester.pump();
       expect(tester.state<FormState>(find.byType(Form)).validate(), true);
 
       await tester.enterText(
-          find.byKey(const Key("flight_log_modal_form_fuel_price")), "ABC");
+          find.byKey(const Key("input_flightLogModal_fuelPrice")), "ABC");
       await tester.pump();
       expect(tester.state<FormState>(find.byType(Form)).validate(), false);
 
       await tester.enterText(
-          find.byKey(const Key("flight_log_modal_form_fuel_price")), "43.2");
+          find.byKey(const Key("input_flightLogModal_fuelPrice")), "43.2");
+      await tester.pump();
+      expect(tester.state<FormState>(find.byType(Form)).validate(), true);
+
+      await tester.enterText(
+          find.byKey(const Key("input_flightLogModal_fuelPrice")), "43.28293");
+      await tester.pump();
+      expect(tester.state<FormState>(find.byType(Form)).validate(), true);
+
+      await tester.enterText(
+          find.byKey(const Key("input_flightLogModal_fuelPrice")), "43.28");
       await tester.pump();
       expect(tester.state<FormState>(find.byType(Form)).validate(), true);
 
       // FIXME this should fail on the locale of the test
       await tester.enterText(
-          find.byKey(const Key("flight_log_modal_form_fuel_price")), "43,2");
+          find.byKey(const Key("input_flightLogModal_fuelPrice")), "43,2");
       await tester.pump();
       expect(tester.state<FormState>(find.byType(Form)).validate(), true);
     });
 
     testWidgets('Fuel amount validation', (tester) async {
-      // TODO
+      FlightLogItem item = FlightLogItem(
+        null,
+        DateTime.now(),
+        'Sara',
+        'Fly@localhost',
+        'Fly@localhost',
+        1238,
+        1238,
+        null,
+        null,
+        null,
+      );
+      await tester.pumpWidget(createSkeletonApp(item));
+
+      await tester.enterText(
+          find.byKey(const Key("input_flightLogModal_fuel")), "42");
+      await tester.pump();
+      expect(tester.state<FormState>(find.byType(Form)).validate(), true);
+
+      await tester.enterText(
+          find.byKey(const Key("input_flightLogModal_fuel")), "ABC");
+      await tester.pump();
+      expect(tester.state<FormState>(find.byType(Form)).validate(), false);
+
+      await tester.enterText(
+          find.byKey(const Key("input_flightLogModal_fuel")), "43.2");
+      await tester.pump();
+      expect(tester.state<FormState>(find.byType(Form)).validate(), true);
+
+      await tester.enterText(
+          find.byKey(const Key("input_flightLogModal_fuel")), "43.28");
+      await tester.pump();
+      expect(tester.state<FormState>(find.byType(Form)).validate(), true);
+
+      await tester.enterText(
+          find.byKey(const Key("input_flightLogModal_fuel")), "43.28");
+      await tester.pump();
+      expect(tester.state<FormState>(find.byType(Form)).validate(), true);
+
+      await tester.enterText(
+          find.byKey(const Key("input_flightLogModal_fuel")), "43.2802");
+      await tester.pump();
+      expect(tester.state<FormState>(find.byType(Form)).validate(), true);
+
+      // FIXME this should fail on the locale of the test
+      await tester.enterText(
+          find.byKey(const Key("input_flightLogModal_fuel")), "43,2");
+      await tester.pump();
+      expect(tester.state<FormState>(find.byType(Form)).validate(), true);
     });
 
     testWidgets('Fuel amount mandatory when fuel cost is greater than zero',
         (tester) async {
-      // TODO
+      FlightLogItem item = FlightLogItem(
+        null,
+        DateTime.now(),
+        'Sara',
+        'Fly@localhost',
+        'Fly@localhost',
+        1238,
+        1238,
+        null,
+        null,
+        null,
+      );
+      await tester.pumpWidget(createSkeletonApp(item));
+
+      await tester.enterText(
+          find.byKey(const Key("input_flightLogModal_fuelPrice")), "102.38");
+      await tester.pump();
+      await tester.tap(find.byKey(const Key('button_flightLogModal_save')));
+      await tester.pump();
+      expect(find.byType(PlatformAlertDialog), findsOneWidget);
+      expect(find.text(lang.flightLogModal_error_invalid_fuel_empty),
+          findsOneWidget);
     });
 
     testWidgets('Fuel cost mandatory when fuel amount is greater than zero',
         (tester) async {
-      // TODO
+      FlightLogItem item = FlightLogItem(
+        null,
+        DateTime.now(),
+        'Sara',
+        'Fly@localhost',
+        'Fly@localhost',
+        1238,
+        1238,
+        null,
+        null,
+        null,
+      );
+      await tester.pumpWidget(createSkeletonApp(item));
+
+      await tester.enterText(
+          find.byKey(const Key("input_flightLogModal_fuel")), "102.38");
+      await tester.pump();
+      await tester.tap(find.byKey(const Key('button_flightLogModal_save')));
+      await tester.pump();
+      expect(find.byType(PlatformAlertDialog), findsOneWidget);
+      expect(find.text(lang.flightLogModal_error_invalid_fuelCost_empty),
+          findsOneWidget);
     });
   });
 }