dartfmt gets opinionated about 'gratuitous' linebreaks.

pkg/analyzer/test/services/formatter_test.dart

 // Copyright (c) 2013, 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:unittest/unittest.dart';
 
 import 'package:analyzer/src/generated/java_core.dart' show CharSequence;
 import 'package:analyzer/src/generated/scanner.dart';
 import 'package:analyzer/src/services/formatter_impl.dart';
 import 'package:analyzer/src/services/writer.dart';
@@ skipping 548 matching lines @@
     test('CU - comments (10)', () {
       expectCUFormatsTo(
           'var l = [1 /* bang */, 2];\n',
           'var l = [1 /* bang */, 2];\n'
       );
     });
 
     test('CU - comments (11)', () {
       expectCUFormatsTo(
           'var m = {1: 2 /* bang */, 3: 4};\n',
-          'var m = {1: 2 /* bang */, 3: 4};\n'
+          'var m = {\n'
+          '  1: 2 /* bang */,\n'
+          '  3: 4\n'
+          '};\n'
       );
     });
 
     test('CU - EOF nl', () {
       expectCUFormatsTo(
           'var x = 1;',
           'var x = 1;\n'
       );
     });
 
@@ skipping 200 matching lines @@
     test('stmt (lists)', () {
       expectStmtFormatsTo(
         'var l = [1,2,3,4];',
         'var l = [1, 2, 3, 4];'
       );
       expectStmtFormatsTo(
         'var l = [\n'
         '1,\n'
         '2,\n'
         '];',
-        'var l = [\n'
-        '  1,\n'
-        '  2,\n'
-        '];'
+        'var l = [1, 2,];'
       );
       //Dangling ','
       expectStmtFormatsTo(
         'var l = [1,];',
         'var l = [1,];'
       );
     });
 
     test('stmt (maps)', () {
       expectStmtFormatsTo(
         'var map = const {"foo": "bar", "fuz": null};',
-        'var map = const {"foo": "bar", "fuz": null};'
+        'var map = const {\n'
+        '  "foo": "bar",\n'
+        '  "fuz": null\n'
+        '};'
       );
 
       expectStmtFormatsTo(
           'var map = {\n'
           '"foo": "bar",\n'
-          '"bar": "baz"'
+          '"bar": "baz"\n'
           '};',
           'var map = {\n'
           '  "foo": "bar",\n'
-          '  "bar": "baz"'
+          '  "bar": "baz"\n'
           '};'
       );
 
       //Dangling ','
       expectStmtFormatsTo(
         'var map = {"foo": "bar",};',
-        'var map = {"foo": "bar",};'
+        'var map = {\n'
+        '  "foo": "bar",\n'
+        '};'
       );
     });
 
     test('stmt (try/catch)', () {
       expectStmtFormatsTo(
         'try {\n'
         'doSomething();\n'
         '} catch (e) {\n'
         'print(e);\n'
         '}',
@@ skipping 74 matching lines @@
                           'if (true) {\n'
                           '  print("true!");\n'
                           '} else {\n'
                           '  print("false!");\n'
                           '}');
       expectStmtFormatsTo('if (true) print("true!"); else print("false!");',
                           'if (true) print("true!"); else print("false!");',
                           transforms: false);
     });
 
+    // smoketest to ensure we're enforcing the 'no gratuitous linebreaks'
+    // opinion
+    test('CU (eat newlines)', () {
+      expectCUFormatsTo(
+        'abstract\n'
+        'class\n'
+        'A{}',
+        'abstract class A {\n'
+        '}\n'
+      );
+    });
+
 //    test('line continuations - 1', () {
 //      expectStmtFormatsTo(
 //          'if (x &&\n'
 //          '    y) {\n'
 //          '  print("yes!");\n'
 //          '}',
 //          'if (x &&\n'
 //          '    y) {\n'
 //          '  print("yes!");\n'
 //          '}'
@@ skipping 338 matching lines @@
     expect(() => new TokenStreamComparator(null, t1, t2).verifyEquals(),
     throwsA(new isInstanceOf<FormatterException>()));
 
 expectCUFormatsTo(src, expected, {transforms: true}) =>
     expect(formatCU(src, options: new FormatterOptions(
         codeTransforms: transforms)).source, equals(expected));
 
 expectStmtFormatsTo(src, expected, {transforms: true}) =>
     expect(formatStatement(src, options:
       new FormatterOptions(codeTransforms: transforms)), equals(expected));