CaffeineService tests

lib/data/caffeine_service.dart

@@ -9,7 +9,7 @@ class CaffeineService {
     return _methodChannel.invokeMethod<bool>("isKeepScreenOn").then((value) => value!);
   }
 
-  Future<void> keepScreenOn(bool keep) async {
+  Future<bool> keepScreenOn(bool keep) async {
-    await _methodChannel.invokeMethod<bool>("setKeepScreenOn", keep);
+    return _methodChannel.invokeMethod<bool>("setKeepScreenOn", keep).then((value) => value!);
   }
 }

test/data/caffeine_service_test.dart

@@ -0,0 +1,76 @@
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:lightmeter/data/caffeine_service.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
+  late CaffeineService service;
+
+  const methodChannel = MethodChannel('com.vodemn.lightmeter/keepScreenOn');
+  Future<Object?>? cameraMethodCallSuccessHandler(MethodCall methodCall) async {
+    switch (methodCall.method) {
+      case "isKeepScreenOn":
+        return true;
+      case "setKeepScreenOn":
+        return methodCall.arguments as bool;
+      default:
+        return null;
+    }
+  }
+
+  setUp(() {
+    service = const CaffeineService();
+    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
+        .setMockMethodCallHandler(methodChannel, cameraMethodCallSuccessHandler);
+  });
+
+  tearDown(() {
+    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
+        .setMockMethodCallHandler(methodChannel, null);
+  });
+
+  group(
+    'isKeepScreenOn()',
+    () {
+      test('true', () async {
+        TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
+            .setMockMethodCallHandler(methodChannel, null);
+        TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
+            .setMockMethodCallHandler(methodChannel, (methodCall) async {
+          switch (methodCall.method) {
+            case "isKeepScreenOn":
+              return true;
+            default:
+              return null;
+          }
+        });
+        expectLater(service.isKeepScreenOn(), completion(true));
+      });
+
+      test('false', () async {
+        TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
+            .setMockMethodCallHandler(methodChannel, null);
+        TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
+            .setMockMethodCallHandler(methodChannel, (methodCall) async {
+          switch (methodCall.method) {
+            case "isKeepScreenOn":
+              return false;
+            default:
+              return null;
+          }
+        });
+        expectLater(service.isKeepScreenOn(), completion(false));
+      });
+    },
+  );
+
+  group(
+    'keepScreenOn()',
+    () {
+      test('true', () async => expectLater(service.keepScreenOn(true), completion(true)));
+
+      test('false', () async => expectLater(service.keepScreenOn(false), completion(false)));
+    },
+  );
+}