Split serialization tests further

tests/compiler/dart2js/serialization/test_helper.dart

 // Copyright (c) 2016, 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.
 
 library dart2js.serialization_test_helper;
 
 import 'dart:collection';
 import 'package:compiler/src/common/resolution.dart';
 import 'package:compiler/src/constants/expressions.dart';
 import 'package:compiler/src/dart_types.dart';
 import 'package:compiler/src/compiler.dart';
 import 'package:compiler/src/elements/elements.dart';
 import 'package:compiler/src/serialization/equivalence.dart';
 import 'package:compiler/src/tree/nodes.dart';
 import 'package:expect/expect.dart';
+import 'test_data.dart';
 
 Check currentCheck;
 
 class Check {
   final Check parent;
   final Object object1;
   final Object object2;
   final String property;
   final Object value1;
   final Object value2;
@@ skipping 556 matching lines @@
 
   if (resolvedAst1 == null || resolvedAst2 == null) return;
 
   if (verbose) {
     print('Checking resolved asts for $member1 vs $member2');
   }
 
   testResolvedAstEquivalence(
       resolvedAst1, resolvedAst2, const CheckStrategy());
 }
+
+/// Return the test arguments for testing the [index]th segment (1-based) of

[Bill Hesse, 2016/07/20 13:46:45]

I think you should have two functions, one for returning a single test, and
another for returning a computed range.  That is better than overloading
negative numbers.

Could you also check the values against skip and count, to make sure they are
valid?

[Johnni Winther, 2016/07/25 08:30:08]

Done.

+/// the [TESTS] split into [count] groups. The first [skip] tests are excluded
+/// from the automatic grouping and tested if `index <= 0`.
+List<String> testSegment(int index, int count, int skip) {
+
+  int segmentNumber(int i) {
+    return skip + i * (TESTS.length - skip) ~/ count;
+  }
+
+  if (index <= 0) {
+    return ['${-index}', '${-index}'];
+  } else if (index == 1 && skip != 0) {
+    return ['${skip}', '${segmentNumber(index) - 1}'];
+  } else if (index  == count) {
+    return ['${segmentNumber(index - 1)}'];
+  } else {
+    return ['${segmentNumber(index - 1)}', '${segmentNumber(index) - 1}'];
+  }
+}