diff --git a/packages/flutter_migrate/test/src/fakes.dart b/packages/flutter_migrate/test/src/fakes.dart
index 498213a6f7b0..fda5a28879bb 100644
--- a/packages/flutter_migrate/test/src/fakes.dart
+++ b/packages/flutter_migrate/test/src/fakes.dart
@@ -132,6 +132,15 @@ class MemoryStdout extends MemoryIOSink implements io.Stdout {
 
   bool _hasTerminal = true;
 
+  @override
+  // ignore: override_on_non_overriding_member
+  String get lineTerminator => '\n';
+  @override
+  // ignore: override_on_non_overriding_member
+  set lineTerminator(String value) {
+    throw UnimplementedError('Setting the line terminator is not supported');
+  }
+
   @override
   io.IOSink get nonBlocking => this;