Check in codegen test expectations.

test/codegen/expect/corelib/map_to_string_test.js

Index: test/codegen/expect/corelib/map_to_string_test.js
diff --git a/test/codegen/expect/corelib/map_to_string_test.js b/test/codegen/expect/corelib/map_to_string_test.js
new file mode 100644
index 0000000000000000000000000000000000000000..b88d25e71a94f7c244ce4ce70e61bc77917d891d
--- /dev/null
+++ b/test/codegen/expect/corelib/map_to_string_test.js
@@ -0,0 +1,36 @@
+dart_library.library('corelib/map_to_string_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__map_to_string_test(exports, dart_sdk, expect) {
+  'use strict';
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const expect$ = expect.expect;
+  const map_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, [])))();
+  map_to_string_test.main = function() {
+    let m = core.Map.new();
+    m[dartx.set](0, 0);
+    m[dartx.set](1, 1);
+    m[dartx.set](2, m);
+    expect$.Expect.equals('{0: 0, 1: 1, 2: {...}}', dart.toString(m));
+    let err = new map_to_string_test.ThrowOnToString();
+    m[dartx.set](1, err);
+    expect$.Expect.throws(dart.bind(m, 'toString', dart.toString), dart.fn(e => dart.equals(e, "Bad!"), dynamicTobool()));
+    m[dartx.set](1, 1);
+    expect$.Expect.equals('{0: 0, 1: 1, 2: {...}}', dart.toString(m));
+    m[dartx.set](err, 1);
+    expect$.Expect.throws(dart.bind(m, 'toString', dart.toString), dart.fn(e => dart.equals(e, "Bad!"), dynamicTobool()));
+    m[dartx.remove](err);
+  };
+  dart.fn(map_to_string_test.main, VoidTovoid());
+  map_to_string_test.ThrowOnToString = class ThrowOnToString extends core.Object {
+    toString() {
+      dart.throw("Bad!");
+    }
+  };
+  // Exports:
+  exports.map_to_string_test = map_to_string_test;
+});