diff --git a/packages/flutter_test/lib/src/goldens.dart b/packages/flutter_test/lib/src/goldens.dart
index 537cca0..8a141a9 100644
--- a/packages/flutter_test/lib/src/goldens.dart
+++ b/packages/flutter_test/lib/src/goldens.dart
@@ -125,8 +125,7 @@
   ///
   /// The [testFile] URI must represent a file.
   LocalFileComparator(Uri testFile, {path.Style pathStyle})
-      : assert(testFile.scheme == 'file'),
-        basedir = _getBasedir(testFile, pathStyle),
+      : basedir = _getBasedir(testFile, pathStyle),
         _path = _getPath(pathStyle);
 
   static path.Context _getPath(path.Style style) {
@@ -135,7 +134,9 @@
 
   static Uri _getBasedir(Uri testFile, path.Style pathStyle) {
     final path.Context context = _getPath(pathStyle);
-    return context.toUri(context.dirname(context.fromUri(testFile)) + context.separator);
+    final String testFilePath = context.fromUri(testFile);
+    final String testDirectoryPath = context.dirname(testFilePath);
+    return context.toUri(testDirectoryPath + context.separator);
   }
 
   /// The directory in which the test was loaded.
diff --git a/packages/flutter_test/test/goldens_test.dart b/packages/flutter_test/test/goldens_test.dart
index b84ed09..e93945b 100644
--- a/packages/flutter_test/test/goldens_test.dart
+++ b/packages/flutter_test/test/goldens_test.dart
@@ -78,6 +78,11 @@
       expect(comparator.basedir, fs.directory(fix('/foo/bar/')).uri);
     });
 
+    test('can be instantiated with uri that represents file in same folder', () {
+      comparator = new LocalFileComparator(Uri.parse('foo_test.dart'), pathStyle: fs.path.style);
+      expect(comparator.basedir, Uri.parse('./'));
+    });
+
     group('compare', () {
       Future<bool> doComparison([String golden = 'golden.png']) {
         final Uri uri = fs.file(fix(golden)).uri;
@@ -101,6 +106,28 @@
           final bool success = await doComparison('sub/foo.png');
           expect(success, isTrue);
         });
+
+        group('when comparator instantiated with uri that represents file in same folder', () {
+          test('and golden file is in same folder as test', () async {
+            fs.file(fix('/foo/bar/golden.png'))
+              ..createSync(recursive: true)
+              ..writeAsBytesSync(_kExpectedBytes);
+            fs.currentDirectory = fix('/foo/bar');
+            comparator = new LocalFileComparator(Uri.parse('local_test.dart'), pathStyle: fs.path.style);
+            final bool success = await doComparison('golden.png');
+            expect(success, isTrue);
+          });
+
+          test('and golden file is in subfolder of test', () async {
+            fs.file(fix('/foo/bar/baz/golden.png'))
+              ..createSync(recursive: true)
+              ..writeAsBytesSync(_kExpectedBytes);
+            fs.currentDirectory = fix('/foo/bar');
+            comparator = new LocalFileComparator(Uri.parse('local_test.dart'), pathStyle: fs.path.style);
+            final bool success = await doComparison('baz/golden.png');
+            expect(success, isTrue);
+          });
+        });
       });
 
       group('fails', () {
diff --git a/packages/flutter_tools/lib/src/test/flutter_platform.dart b/packages/flutter_tools/lib/src/test/flutter_platform.dart
index b2e68a0..bc2c8c1 100644
--- a/packages/flutter_tools/lib/src/test/flutter_platform.dart
+++ b/packages/flutter_tools/lib/src/test/flutter_platform.dart
@@ -95,6 +95,95 @@
   );
 }
 
+/// Generates the bootstrap entry point script that will be used to launch an
+/// individual test file.
+///
+/// The [testUrl] argument specifies the path to the test file that is being
+/// launched.
+///
+/// The [host] argument specifies the address at which the test harness is
+/// running.
+///
+/// If [testConfigFile] is specified, it must follow the conventions of test
+/// configuration files as outlined in the [flutter_test] library. By default,
+/// the test file will be launched directly.
+///
+/// The [updateGoldens] argument will set the [autoUpdateGoldens] global
+/// variable in the [flutter_test] package before invoking the test.
+String generateTestBootstrap({
+  @required Uri testUrl,
+  @required InternetAddress host,
+  File testConfigFile,
+  bool updateGoldens: false,
+}) {
+  assert(testUrl != null);
+  assert(host != null);
+  assert(updateGoldens != null);
+
+  final String websocketUrl = host.type == InternetAddressType.IP_V4 // ignore: deprecated_member_use
+      ? 'ws://${host.address}'
+      : 'ws://[${host.address}]';
+  final String encodedWebsocketUrl = Uri.encodeComponent(websocketUrl);
+
+  final StringBuffer buffer = new StringBuffer();
+  buffer.write('''
+import 'dart:convert';
+import 'dart:io';  // ignore: dart_io_import
+
+// We import this library first in order to trigger an import error for
+// package:test (rather than package:stream_channel) when the developer forgets
+// to add a dependency on package:test.
+import 'package:test/src/runner/plugin/remote_platform_helpers.dart';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:stream_channel/stream_channel.dart';
+import 'package:test/src/runner/vm/catch_isolate_errors.dart';
+
+import '$testUrl' as test;
+'''
+  );
+  if (testConfigFile != null) {
+    buffer.write('''
+import '${new Uri.file(testConfigFile.path)}' as test_config;
+'''
+    );
+  }
+  buffer.write('''
+
+void main() {
+  print('$_kStartTimeoutTimerMessage');
+  String serverPort = Platform.environment['SERVER_PORT'];
+  String server = Uri.decodeComponent('$encodedWebsocketUrl:\$serverPort');
+  StreamChannel channel = serializeSuite(() {
+    catchIsolateErrors();
+    goldenFileComparator = new LocalFileComparator(Uri.parse('$testUrl'));
+    autoUpdateGoldenFiles = $updateGoldens;
+'''
+  );
+  if (testConfigFile != null) {
+    buffer.write('''
+    return () => test_config.main(test.main);
+''');
+  } else {
+    buffer.write('''
+    return test.main;
+''');
+  }
+  buffer.write('''
+  });
+  WebSocket.connect(server).then((WebSocket socket) {
+    socket.map((dynamic x) {
+      assert(x is String);
+      return json.decode(x);
+    }).pipe(channel.sink);
+    socket.addStream(channel.stream.map(json.encode));
+  });
+}
+'''
+  );
+  return buffer.toString();
+}
+
 enum _InitialResult { crashed, timedOut, connected }
 enum _TestResult { crashed, harnessBailed, testBailed }
 typedef Future<Null> _Finalizer();
@@ -581,7 +670,6 @@
     listenerFile.createSync();
     listenerFile.writeAsStringSync(_generateTestMain(
       testUrl: fs.path.toUri(fs.path.absolute(testPath)),
-      encodedWebsocketUrl: Uri.encodeComponent(_getWebSocketUrl()),
     ));
     return listenerFile.path;
   }
@@ -621,15 +709,8 @@
     return tempBundleDirectory.path;
   }
 
-  String _getWebSocketUrl() {
-    return host.type == InternetAddressType.IP_V4 // ignore: deprecated_member_use
-        ? 'ws://${host.address}'
-        : 'ws://[${host.address}]';
-  }
-
   String _generateTestMain({
     Uri testUrl,
-    String encodedWebsocketUrl,
   }) {
     assert(testUrl.scheme == 'file');
     File testConfigFile;
@@ -648,63 +729,12 @@
       }
       directory = directory.parent;
     }
-    final StringBuffer buffer = new StringBuffer();
-    buffer.write('''
-import 'dart:convert';
-import 'dart:io';  // ignore: dart_io_import
-
-// We import this library first in order to trigger an import error for
-// package:test (rather than package:stream_channel) when the developer forgets
-// to add a dependency on package:test.
-import 'package:test/src/runner/plugin/remote_platform_helpers.dart';
-
-import 'package:flutter_test/flutter_test.dart';
-import 'package:stream_channel/stream_channel.dart';
-import 'package:test/src/runner/vm/catch_isolate_errors.dart';
-
-import '$testUrl' as test;
-'''
+    return generateTestBootstrap(
+      testUrl: testUrl,
+      testConfigFile: testConfigFile,
+      host: host,
+      updateGoldens: updateGoldens,
     );
-    if (testConfigFile != null) {
-      buffer.write('''
-import '${new Uri.file(testConfigFile.path)}' as test_config;
-'''
-      );
-    }
-    buffer.write('''
-
-void main() {
-  print('$_kStartTimeoutTimerMessage');
-  String serverPort = Platform.environment['SERVER_PORT'];
-  String server = Uri.decodeComponent('$encodedWebsocketUrl:\$serverPort');
-  StreamChannel channel = serializeSuite(() {
-    catchIsolateErrors();
-    goldenFileComparator = new LocalFileComparator(Uri.parse('$testUrl'));
-    autoUpdateGoldenFiles = $updateGoldens;
-'''
-    );
-    if (testConfigFile != null) {
-      buffer.write('''
-    return () => test_config.main(test.main);
-''');
-    } else {
-      buffer.write('''
-    return test.main;
-''');
-    }
-    buffer.write('''
-  });
-  WebSocket.connect(server).then((WebSocket socket) {
-    socket.map((dynamic x) {
-      assert(x is String);
-      return json.decode(x);
-    }).pipe(channel.sink);
-    socket.addStream(channel.stream.map(json.encode));
-  });
-}
-'''
-    );
-    return buffer.toString();
   }
 
   File _cachedFontConfig;