Check in codegen test expectations.

test/codegen/expect/corelib/set_to_string_test.js

Index: test/codegen/expect/corelib/set_to_string_test.js
diff --git a/test/codegen/expect/corelib/set_to_string_test.js b/test/codegen/expect/corelib/set_to_string_test.js
new file mode 100644
index 0000000000000000000000000000000000000000..0cc7099186e844e23b16a354a1e4a71de6ca91cc
--- /dev/null
+++ b/test/codegen/expect/corelib/set_to_string_test.js
@@ -0,0 +1,40 @@
+dart_library.library('corelib/set_to_string_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__set_to_string_test(exports, dart_sdk, expect) {
+  'use strict';
+  const core = dart_sdk.core;
+  const collection = dart_sdk.collection;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const expect$ = expect.expect;
+  const set_to_string_test = Object.create(null);
+  let dynamicTobool = () => (dynamicTobool = dart.constFn(dart.definiteFunctionType(core.bool, [dart.dynamic])))();
+  let VoidTovoid = () => (VoidTovoid = dart.constFn(dart.definiteFunctionType(dart.void, [])))();
+  set_to_string_test.main = function() {
+    let s = collection.HashSet.new();
+    s.add(1);
+    expect$.Expect.equals("{1}", s.toString());
+    s.remove(1);
+    s.add(s);
+    expect$.Expect.equals("{{...}}", s.toString());
+    let q = new collection.ListQueue(4);
+    q.add(1);
+    q.add(2);
+    q.add(q);
+    q.add(s);
+    expect$.Expect.equals("{1, 2, {...}, {{...}}}", q.toString());
+    q.addLast(new set_to_string_test.ThrowOnToString());
+    expect$.Expect.throws(dart.bind(q, 'toString'), dart.fn(e => dart.equals(e, "Bad!"), dynamicTobool()));
+    q.removeLast();
+    expect$.Expect.equals("{1, 2, {...}, {{...}}}", q.toString());
+  };
+  dart.fn(set_to_string_test.main, VoidTovoid());
+  set_to_string_test.ThrowOnToString = class ThrowOnToString extends core.Object {
+    toString() {
+      dart.throw("Bad!");
+    }
+  };
+  // Exports:
+  exports.set_to_string_test = set_to_string_test;
+});