throw when parsing invalid orientation

Author: navaronbracke

lib/src/method_channel/android_surface_producer_delegate.dart

@@ -34,30 +34,10 @@ class AndroidSurfaceProducerDelegate {
           'naturalDeviceOrientation': final String naturalDeviceOrientation,
           'sensorOrientation': final int sensorOrientation
         }) {
-      final DeviceOrientation? currentOrientation =
-          deviceOrientation.tryParseDeviceOrientation();
-      final DeviceOrientation? naturalOrientation =
-          naturalDeviceOrientation.tryParseDeviceOrientation();
-
-      if (currentOrientation == null) {
-        throw const MobileScannerException(
-          errorCode: MobileScannerErrorCode.genericError,
-          errorDetails: MobileScannerErrorDetails(
-            message:
-                'The start method did not return a valid current device orientation.',
-          ),
-        );
-      }
-
-      if (naturalOrientation == null) {
-        throw const MobileScannerException(
-          errorCode: MobileScannerErrorCode.genericError,
-          errorDetails: MobileScannerErrorDetails(
-            message:
-                'The start method did not return a valid natural device orientation.',
-          ),
-        );
-      }
+      final DeviceOrientation currentOrientation =
+          deviceOrientation.parseDeviceOrientation();
+      final DeviceOrientation naturalOrientation =
+          naturalDeviceOrientation.parseDeviceOrientation();
 
       return AndroidSurfaceProducerDelegate(
         cameraIsFrontFacing: cameraDirection == CameraFacing.front,

lib/src/utils/parse_device_orientation_extension.dart

@@ -5,15 +5,19 @@ import 'package:flutter/services.dart';
 extension ParseDeviceOrientation on String {
   /// Parse `this` into a [DeviceOrientation].
   ///
-  /// Returns the parsed device orientation,
-  /// or null if `this` is not a valid device orientation.
-  DeviceOrientation? tryParseDeviceOrientation() {
+  /// Returns the parsed device orientation.
+  /// Throws an [ArgumentError] if `this` is an invalid device orientation.
+  DeviceOrientation parseDeviceOrientation() {
     return switch (this) {
       'PORTRAIT_UP' => DeviceOrientation.portraitUp,
       'PORTRAIT_DOWN' => DeviceOrientation.portraitDown,
       'LANDSCAPE_LEFT' => DeviceOrientation.landscapeLeft,
       'LANDSCAPE_RIGHT' => DeviceOrientation.landscapeRight,
-      _ => null,
+      _ => throw ArgumentError.value(
+          this,
+          'deviceOrientation',
+          'Received an invalid device orientation',
+        ),
     };
   }
 }

test/parse_device_orientation_test.dart

@@ -0,0 +1,51 @@
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mobile_scanner/src/utils/parse_device_orientation_extension.dart';
+
+void main() {
+  group('parseDeviceOrientation', () {
+    test('can parse valid device orientation string', () {
+      expect(
+        'PORTRAIT_UP'.parseDeviceOrientation(),
+        DeviceOrientation.portraitUp,
+      );
+      expect(
+        'PORTRAIT_DOWN'.parseDeviceOrientation(),
+        DeviceOrientation.portraitDown,
+      );
+      expect(
+        'LANDSCAPE_LEFT'.parseDeviceOrientation(),
+        DeviceOrientation.landscapeLeft,
+      );
+      expect(
+        'LANDSCAPE_RIGHT'.parseDeviceOrientation(),
+        DeviceOrientation.landscapeRight,
+      );
+    });
+
+    test('throws ArgumentError when parsing invalid device orientation string',
+        () {
+      expect(
+        () => ''.parseDeviceOrientation(),
+        throwsA(
+          isA<ArgumentError>().having(
+            (error) => error.message,
+            'message',
+            'Received an invalid device orientation',
+          ),
+        ),
+      );
+
+      expect(
+        () => 'foo'.parseDeviceOrientation(),
+        throwsA(
+          isA<ArgumentError>().having(
+            (error) => error.message,
+            'message',
+            'Received an invalid device orientation',
+          ),
+        ),
+      );
+    });
+  });
+}