diff --git a/build_runner/test/entrypoint/run_test.dart b/build_runner/test/entrypoint/run_test.dart
index ad147a307..0a32527e0 100644
--- a/build_runner/test/entrypoint/run_test.dart
+++ b/build_runner/test/entrypoint/run_test.dart
@@ -36,7 +36,6 @@ void main() {
       ),
       d.dir('test', [
         d.file('hello_test.dart', '''
-// @dart=2.9
 import 'package:test/test.dart';
 main() {
   test('hello', () {});
diff --git a/build_runner/test/integration_tests/utils/build_descriptor.dart b/build_runner/test/integration_tests/utils/build_descriptor.dart
index d6658786f..45c4af898 100644
--- a/build_runner/test/integration_tests/utils/build_descriptor.dart
+++ b/build_runner/test/integration_tests/utils/build_descriptor.dart
@@ -151,7 +151,6 @@ Future<BuildTool> packageWithBuildScript(
 String _buildersFile(
         Iterable<TestBuilderDefinition> builders, Uri callingScript) =>
     '''
-// @dart=2.9
 import 'package:build/build.dart';
 import 'package:build_test/build_test.dart';
 
@@ -166,7 +165,6 @@ String _builderFactory(TestBuilderDefinition builder) =>
 String _buildToolFile(
         Iterable<TestBuilderDefinition> builders, Uri callingScript) =>
     '''
-// @dart=2.9
 import 'dart:io';
 
 import 'package:build/build.dart';
@@ -236,7 +234,7 @@ d.FileDescriptor _pubspec(String name,
   var buffer = StringBuffer()
     ..writeln('name: $name')
     ..writeln('environment:')
-    ..writeln('  sdk: ">=2.9.0 <3.0.0"');
+    ..writeln('  sdk: ">=2.12.0 <3.0.0"');
 
   void writeDeps(String group) {
     buffer.writeln(group);
diff --git a/build_test/test/test_bootstrap_builder_test.dart b/build_test/test/test_bootstrap_builder_test.dart
index c92f28111..8b1924036 100644
--- a/build_test/test/test_bootstrap_builder_test.dart
+++ b/build_test/test/test_bootstrap_builder_test.dart
@@ -1,7 +1,6 @@
 // Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
-// @dart=2.9
 
 import 'package:build_test/build_test.dart';
 import 'package:build_test/builder.dart';