Work in progress: front end hot reload API

pkg/front_end/test/incremental_resolved_ast_generator_test.dart

+// Copyright (c) 2017, 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.
+
+import 'dart:async';
+
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/file_system/physical_file_system.dart';
+import 'package:analyzer/src/dart/sdk/sdk.dart';
+import 'package:front_end/compiler_options.dart';
+import 'package:front_end/incremental_resolved_ast_generator.dart';
+import 'package:front_end/memory_file_system.dart';
+import 'package:path/path.dart' as pathos;
+import 'package:test/test.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+
+main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(IncrementalResolvedAstGeneratorTest);
+  });
+}
+
+final _sdkSummary = _readSdkSummary();
+
+List<int> _readSdkSummary() {
+  var resourceProvider = PhysicalResourceProvider.INSTANCE;
+  var sdk = new FolderBasedDartSdk(resourceProvider,
+      FolderBasedDartSdk.defaultSdkDirectory(resourceProvider))
+    ..useSummary = true;
+  var path = resourceProvider.pathContext
+      .join(sdk.directory.path, 'lib', '_internal', 'strong.sum');
+  return resourceProvider.getFile(path).readAsBytesSync();
+}
+
+@reflectiveTest
+class IncrementalResolvedAstGeneratorTest {
+  static final sdkSummaryUri = Uri.parse('special:sdk_summary');
+
+  /// Virtual filesystem for testing.
+  final fileSystem = new MemoryFileSystem(pathos.posix, Uri.parse('file:///'));
+
+  /// The object under test.
+  IncrementalResolvedAstGenerator incrementalResolvedAstGenerator;
+
+  Future<Map<Uri, ResolvedLibrary>> getInitialProgram(Uri startingUri) async {
+    fileSystem.entityForUri(sdkSummaryUri).writeAsBytesSync(_sdkSummary);
+    incrementalResolvedAstGenerator = new IncrementalResolvedAstGenerator(
+        startingUri,
+        new CompilerOptions()
+          ..fileSystem = fileSystem
+          ..chaseDependencies = true
+          ..sdkSummary = sdkSummaryUri
+          ..packagesFileUri = new Uri());
+    return (await incrementalResolvedAstGenerator.computeDelta()).newState;
+  }
+
+  test_emptyProgram() async {
+    writeFiles({'/foo.dart': 'main() {}'});
+    var fooUri = Uri.parse('file:///foo.dart');
+    var initialProgram = await getInitialProgram(fooUri);
+    expect(initialProgram.keys, unorderedEquals([fooUri]));
+    var unit = initialProgram[fooUri].definingCompilationUnit;
+    expect(unit.declarations, hasLength(1));
+    expect(unit.declarations[0], new isInstanceOf<FunctionDeclaration>());
+    var main = unit.declarations[0] as FunctionDeclaration;
+    expect(main.name.name, 'main');
+    // TODO(paulberry): test that stuff is actually resolved.
+    // TODO(paulberry): test parts.
+  }
+
+  /// Write the given file contents to the virtual filesystem.
+  void writeFiles(Map<String, String> contents) {
+    contents.forEach((path, text) {
+      fileSystem
+          .entityForUri(Uri.parse('file://$path'))
+          .writeAsStringSync(text);
+    });
+  }
+}