Add an integration test for edit.format.

pkg/analysis_server/test/integration/edit/format_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 'package:analysis_server/plugin/protocol/protocol.dart';
+import 'package:test/test.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+
+import '../integration_tests.dart';
+
+main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(FormatTest);
+  });
+}
+
+@reflectiveTest
+class FormatTest extends AbstractAnalysisServerIntegrationTest {
+  String setup({bool withErrors: false}) {

[Brian Wilkerson, 2017/02/15 14:58:42]

Perhaps a different name so that people will know that you didn't mean "setUp".

[devoncarew, 2017/02/15 15:22:51]

Good point; renamed to 'formatTestSetup'.

+    String pathname = sourcePath('test.dart');
+
+    if (withErrors) {
+      String text = r'''
+class Class1 {
+  int field
+  void foo() {
+  }
+}
+''';
+      writeFile(pathname, text);
+    } else {
+      String text = r'''
+class Class1 {
+  int field;
+
+  void foo() {
+  }
+
+  void bar() {
+  }
+}
+''';
+      writeFile(pathname, text);
+    }
+    standardAnalysisSetup();
+    return pathname;
+  }
+
+  test_format() async {
+    String pathname = setup();
+
+    EditFormatResult result = await sendEditFormat(pathname, 0, 0);
+    expect(result.edits, isNotEmpty);
+    expect(result.selectionOffset, 0);
+    expect(result.selectionLength, 0);
+  }
+
+  test_format_preserve_selection() async {
+    String pathname = setup();
+
+    // format with 'bar' selected
+    int initialPosition = readFile(pathname).indexOf('bar()');

[Brian Wilkerson, 2017/02/15 14:58:42]

The test will run faster if you capture the initial position in `setup` rather
than by reading the file.

[devoncarew, 2017/02/15 15:22:51]

I slightly prefer this as we only have to get one value back from the
formatTestSetup() method - the file name. I/O will be pretty fast in comparison
to the integration test speed.

[Brian Wilkerson, 2017/02/15 15:27:54]

I was thinking about assigning the value to a field, not returning it.
Our time allotment for tests is very small, so anything we can do to reduce the
time any individual test takes will reduce the number of flaky tests we have.
Also, test performance has a major impact on productivity.

+    EditFormatResult result =
+        await sendEditFormat(pathname, initialPosition, 'bar'.length);
+    expect(result.edits, isNotEmpty);
+    expect(result.selectionOffset, initialPosition - 3);
+    expect(result.selectionLength, 'bar'.length);
+  }
+
+  test_format_with_errors() async {
+    String pathname = setup(withErrors: true);
+
+    try {
+      await sendEditFormat(pathname, 0, 0);
+      fail('expected FORMAT_WITH_ERRORS');
+    } on ServerErrorMessage catch (message) {
+      expect(message.error['code'], 'FORMAT_WITH_ERRORS');
+    }
+  }
+
+  @override
+  bool get enableNewAnalysisDriver => true;
+}