diff --git a/.packages b/.packages
index d5914345260..aa7918c492d 100644
--- a/.packages
+++ b/.packages
@@ -82,6 +82,7 @@ shelf_packages_handler:third_party/pkg/shelf_packages_handler/lib
 shelf_static:third_party/pkg/shelf_static/lib
 shelf_web_socket:third_party/pkg/shelf_web_socket/lib
 source_map_stack_trace:third_party/pkg/source_map_stack_trace/lib
+sourcemap_testing:pkg/sourcemap_testing/lib
 source_maps:third_party/pkg/source_maps/lib
 source_span:third_party/pkg/source_span/lib
 stack_trace:third_party/pkg/stack_trace/lib
diff --git a/tests/compiler/dart2js/annotated_code_helper.dart b/pkg/sourcemap_testing/lib/src/annotated_code_helper.dart
similarity index 100%
rename from tests/compiler/dart2js/annotated_code_helper.dart
rename to pkg/sourcemap_testing/lib/src/annotated_code_helper.dart
diff --git a/tests/compiler/dart2js/sourcemaps/helpers/stacktrace_helper.dart b/pkg/sourcemap_testing/lib/src/stacktrace_helper.dart
similarity index 99%
rename from tests/compiler/dart2js/sourcemaps/helpers/stacktrace_helper.dart
rename to pkg/sourcemap_testing/lib/src/stacktrace_helper.dart
index 3245fa851df..9ee7c425a60 100644
--- a/tests/compiler/dart2js/sourcemaps/helpers/stacktrace_helper.dart
+++ b/pkg/sourcemap_testing/lib/src/stacktrace_helper.dart
@@ -9,7 +9,7 @@ import 'package:expect/expect.dart';
 import 'package:source_maps/source_maps.dart';
 import 'package:source_maps/src/utils.dart';
 
-import '../../annotated_code_helper.dart';
+import 'annotated_code_helper.dart';
 
 const String EXCEPTION_MARKER = '>ExceptionMarker<';
 const String INPUT_FILE_NAME = 'in.dart';
diff --git a/pkg/sourcemap_testing/pubspec.yaml b/pkg/sourcemap_testing/pubspec.yaml
new file mode 100644
index 00000000000..c12dcf1b68f
--- /dev/null
+++ b/pkg/sourcemap_testing/pubspec.yaml
@@ -0,0 +1,6 @@
+# Helper package for testing sourcemaps. Used by ddc and dart2js.
+name: sourcemap_testing
+#version: do-not-upload
+dependencies:
+  package_config: '>=0.1.1 <2.0.0'
+  pub_semver: ^1.2.1
diff --git a/tests/compiler/dart2js/equivalence/id_equivalence_helper.dart b/tests/compiler/dart2js/equivalence/id_equivalence_helper.dart
index 9ce56526af6..02219c19443 100644
--- a/tests/compiler/dart2js/equivalence/id_equivalence_helper.dart
+++ b/tests/compiler/dart2js/equivalence/id_equivalence_helper.dart
@@ -16,8 +16,8 @@ import 'package:compiler/src/io/source_file.dart';
 import 'package:compiler/src/source_file_provider.dart';
 import 'package:compiler/src/world.dart';
 import 'package:expect/expect.dart';
+import 'package:sourcemap_testing/src/annotated_code_helper.dart';
 
-import '../annotated_code_helper.dart';
 import '../memory_compiler.dart';
 import '../equivalence/id_equivalence.dart';
 import '../kernel/test_helpers.dart';
diff --git a/tests/compiler/dart2js/equivalence/id_equivalence_test.dart b/tests/compiler/dart2js/equivalence/id_equivalence_test.dart
index 179261e08a1..a7f811b0f76 100644
--- a/tests/compiler/dart2js/equivalence/id_equivalence_test.dart
+++ b/tests/compiler/dart2js/equivalence/id_equivalence_test.dart
@@ -16,7 +16,7 @@ import 'package:compiler/src/resolution/access_semantics.dart';
 import 'package:compiler/src/resolution/send_structure.dart';
 import 'package:compiler/src/tree/nodes.dart' as ast;
 import 'package:kernel/ast.dart' as ir;
-import '../annotated_code_helper.dart';
+import 'package:sourcemap_testing/src/annotated_code_helper.dart';
 import '../equivalence/id_equivalence.dart';
 import '../equivalence/id_equivalence_helper.dart';
 
diff --git a/tests/compiler/dart2js/kernel/run_from_dill_test.dart b/tests/compiler/dart2js/kernel/run_from_dill_test.dart
index 8b45340c118..4d73a3599dc 100644
--- a/tests/compiler/dart2js/kernel/run_from_dill_test.dart
+++ b/tests/compiler/dart2js/kernel/run_from_dill_test.dart
@@ -13,9 +13,9 @@ import 'package:expect/expect.dart';
 import 'package:compiler/src/commandline_options.dart';
 import 'package:compiler/src/dart2js.dart' as dart2js;
 import 'package:compiler/src/filenames.dart';
+import 'package:sourcemap_testing/src/stacktrace_helper.dart';
 
 import 'compiler_helper.dart';
-import '../sourcemaps/helpers/stacktrace_helper.dart';
 import '../serialization/helper.dart';
 
 const SOURCE = const {
diff --git a/tests/compiler/dart2js/sourcemaps/mapping_test.dart b/tests/compiler/dart2js/sourcemaps/mapping_test.dart
index a0cbf9199aa..5a84b3f6d22 100644
--- a/tests/compiler/dart2js/sourcemaps/mapping_test.dart
+++ b/tests/compiler/dart2js/sourcemaps/mapping_test.dart
@@ -10,8 +10,8 @@ import 'package:compiler/compiler_new.dart';
 import 'package:compiler/src/commandline_options.dart';
 import 'package:expect/expect.dart';
 import 'package:source_maps/source_maps.dart';
+import 'package:sourcemap_testing/src/annotated_code_helper.dart';
 
-import '../annotated_code_helper.dart';
 import '../memory_compiler.dart';
 
 const List<String> TESTS = const <String>[
diff --git a/tests/compiler/dart2js/sourcemaps/stacktrace_test.dart b/tests/compiler/dart2js/sourcemaps/stacktrace_test.dart
index 82b75479b10..f4a837cba6b 100644
--- a/tests/compiler/dart2js/sourcemaps/stacktrace_test.dart
+++ b/tests/compiler/dart2js/sourcemaps/stacktrace_test.dart
@@ -11,7 +11,7 @@ import 'package:compiler/compiler_new.dart';
 import 'package:compiler/src/commandline_options.dart';
 import 'package:compiler/src/dart2js.dart' as entry;
 
-import 'helpers/stacktrace_helper.dart';
+import 'package:sourcemap_testing/src/stacktrace_helper.dart';
 
 void main(List<String> args) {
   ArgParser argParser = new ArgParser(allowTrailingOptions: true);