Compute topologically sorted library cycles.

pkg/front_end/test/src/incremental/file_state_test.dart

Index: pkg/front_end/test/src/incremental/file_state_test.dart
diff --git a/pkg/front_end/test/src/incremental/file_state_test.dart b/pkg/front_end/test/src/incremental/file_state_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..0d413b883fe553a10e7b129275a0fe5a0266f2c3
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+++ b/pkg/front_end/test/src/incremental/file_state_test.dart
@@ -0,0 +1,155 @@
+// 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 'package:front_end/memory_file_system.dart';
+import 'package:front_end/src/fasta/translate_uri.dart';
+import 'package:front_end/src/incremental/file_state.dart';
+import 'package:test/test.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+
+import 'mock_sdk.dart';
+
+main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(FileSystemStateTest);
+  });
+}
+
+@reflectiveTest
+class FileSystemStateTest {
+  final fileSystem = new MemoryFileSystem(Uri.parse('file:///'));
+  final TranslateUri uriTranslator = new TranslateUri({}, {});
+  FileSystemState fsState;
+
+  Uri _coreUri;
+
+  void setUp() {
+    Map<String, Uri> dartLibraries = createSdkFiles(fileSystem);
+    uriTranslator.dartLibraries.addAll(dartLibraries);
+    _coreUri = uriTranslator.dartLibraries['core'];
+    expect(_coreUri, isNotNull);
+    fsState = new FileSystemState(fileSystem, uriTranslator);
+  }
+
+  test_getFile() async {
+    var a = writeFile('/a.dart', '');
+    var b = writeFile('/b.dart', '');
+    var c = writeFile('/c.dart', '');
+    var d = writeFile(
+        '/d.dart',
+        r'''
+import "a.dart";
+export "b.dart";
+part "c.dart";
+''');
+
+    FileState aFile = await fsState.getFile(a);
+    FileState bFile = await fsState.getFile(b);
+    FileState cFile = await fsState.getFile(c);
+    FileState dFile = await fsState.getFile(d);
+
+    expect(dFile.fileUri, d);
+    expect(dFile.exists, isTrue);
+    _assertImportedUris(dFile, [a, _coreUri]);
+    expect(dFile.importedLibraries, contains(aFile));
+    expect(dFile.exportedLibraries, contains(bFile));
+    expect(dFile.partFiles, contains(cFile));
+
+    expect(aFile.fileUri, a);
+    expect(aFile.exists, isTrue);
+    _assertImportedUris(aFile, [_coreUri]);
+    expect(aFile.exportedLibraries, isEmpty);
+    expect(aFile.partFiles, isEmpty);
+
+    expect(bFile.fileUri, b);
+    expect(bFile.exists, isTrue);
+    _assertImportedUris(bFile, [_coreUri]);
+    expect(bFile.exportedLibraries, isEmpty);
+    expect(bFile.partFiles, isEmpty);
+  }
+
+  test_topologicalOrder_cycleBeforeTarget() async {
+    var aUri = _writeFileDirectives('/a.dart');
+    var bUri = _writeFileDirectives('/b.dart', imports: ['c.dart']);
+    var cUri = _writeFileDirectives('/c.dart', imports: ['b.dart']);
+    var dUri = _writeFileDirectives('/d.dart', imports: ['a.dart', 'b.dart']);
+
+    FileState core = await fsState.getFile(_coreUri);
+    FileState a = await fsState.getFile(aUri);
+    FileState b = await fsState.getFile(bUri);
+    FileState c = await fsState.getFile(cUri);
+    FileState d = await fsState.getFile(dUri);
+
+    List<LibraryCycle> order = d.topologicalOrder;
+    expect(order, hasLength(4));
+    expect(order[0].libraries, contains(core));
+    expect(order[1].libraries, unorderedEquals([a]));
+    expect(order[2].libraries, unorderedEquals([b, c]));
+    expect(order[3].libraries, unorderedEquals([d]));
+  }
+
+  test_topologicalOrder_cycleBeforeTarget_export() async {
+    var aUri = _writeFileDirectives('/a.dart');
+    var bUri = _writeFileDirectives('/b.dart', exports: ['c.dart']);
+    var cUri = _writeFileDirectives('/c.dart', imports: ['b.dart']);
+    var dUri = _writeFileDirectives('/d.dart', imports: ['a.dart', 'b.dart']);
+
+    FileState core = await fsState.getFile(_coreUri);
+    FileState a = await fsState.getFile(aUri);
+    FileState b = await fsState.getFile(bUri);
+    FileState c = await fsState.getFile(cUri);
+    FileState d = await fsState.getFile(dUri);
+
+    List<LibraryCycle> order = d.topologicalOrder;
+    expect(order, hasLength(4));
+    expect(order[0].libraries, contains(core));
+    expect(order[1].libraries, unorderedEquals([a]));
+    expect(order[2].libraries, unorderedEquals([b, c]));
+    expect(order[3].libraries, unorderedEquals([d]));
+  }
+
+  test_topologicalOrder_cycleWithTarget() async {
+    var aUri = _writeFileDirectives('/a.dart');
+    var bUri = _writeFileDirectives('/b.dart', imports: ['c.dart']);
+    var cUri = _writeFileDirectives('/c.dart', imports: ['a.dart', 'b.dart']);
+
+    FileState core = await fsState.getFile(_coreUri);
+    FileState a = await fsState.getFile(aUri);
+    FileState b = await fsState.getFile(bUri);
+    FileState c = await fsState.getFile(cUri);
+
+    List<LibraryCycle> order = c.topologicalOrder;
+    expect(order, hasLength(3));
+    expect(order[0].libraries, contains(core));
+    expect(order[1].libraries, unorderedEquals([a]));
+    expect(order[2].libraries, unorderedEquals([b, c]));
+  }
+
+  /// Write the given [text] of the file with the given [path] into the
+  /// virtual filesystem.  Return the URI of the file.
+  Uri writeFile(String path, String text) {
+    Uri uri = Uri.parse('file://$path');
+    fileSystem.entityForUri(uri).writeAsStringSync(text);
+    return uri;
+  }
+
+  void _assertImportedUris(FileState file, List<Uri> expectedUris) {
+    Iterable<Uri> importedUris = _toFileUris(file.importedLibraries);
+    expect(importedUris, unorderedEquals(expectedUris));
+  }
+
+  Iterable<Uri> _toFileUris(List<FileState> files) {
+    return files.map((f) => f.fileUri);
+  }
+
+  Uri _writeFileDirectives(String path,
+      {List<String> imports: const [], List<String> exports: const []}) {
+    return writeFile(
+        path,
+        '''
+${imports.map((uri) => 'import "$uri";').join('\n')}
+${exports.map((uri) => 'export "$uri";').join('\n')}
+''');
+  }
+}