Check in codegen test expectations.

test/codegen/expect/corelib/stacktrace_fromstring_test.js

+dart_library.library('corelib/stacktrace_fromstring_test', null, /* Imports */[
+  'dart_sdk',
+  'expect',
+  'async_helper'
+], function load__stacktrace_fromstring_test(exports, dart_sdk, expect, async_helper) {
+  'use strict';
+  const core = dart_sdk.core;
+  const async = dart_sdk.async;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const expect$ = expect.expect;
+  const async_helper$ = async_helper.async_helper;
+  const stacktrace_fromstring_test = Object.create(null);
+  let dynamicTovoid = () => (dynamicTovoid = dart.constFn(dart.definiteFunctionType(dart.void, [dart.dynamic])))();
+  let dynamicAnddynamicTodynamic = () => (dynamicAnddynamicTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [dart.dynamic, dart.dynamic])))();
+  let dynamicTodynamic = () => (dynamicTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [dart.dynamic])))();
+  let VoidTovoid = () => (VoidTovoid = dart.constFn(dart.definiteFunctionType(dart.void, [])))();
+  stacktrace_fromstring_test.main = function() {
+    let stack = null;
+    try {
+      dart.throw(0);
+    } catch (e) {
+      let s = dart.stackTrace(e);
+      stack = s;
+    }
+
+    let string = dart.str`${stack}`;
+    let stringTrace = core.StackTrace.fromString(string);
+    expect$.Expect.isTrue(core.StackTrace.is(stringTrace));
+    expect$.Expect.equals(dart.toString(stack), stringTrace.toString());
+    string = "some random string, nothing like a StackTrace";
+    stringTrace = core.StackTrace.fromString(string);
+    expect$.Expect.isTrue(core.StackTrace.is(stringTrace));
+    expect$.Expect.equals(string, stringTrace.toString());
+    async_helper$.asyncStart();
+    let c = async.Completer.new();
+    c.completeError(0, stringTrace);
+    c.future.then(dart.dynamic)(dart.fn(v => {
+      dart.throw(dart.str`Unexpected value: ${v}`);
+    }, dynamicTodynamic()), {onError: dart.fn((e, s) => {
+        expect$.Expect.equals(string, dart.toString(s));
+      }, dynamicAnddynamicTodynamic())}).then(dart.dynamic)(dart.fn(_ => {
+      let c = async.StreamController.new();
+      c.stream.listen(dart.fn(v => {
+        dart.throw(dart.str`Unexpected value: ${v}`);
+      }, dynamicTovoid()), {onError: dart.fn((e, s) => {
+          expect$.Expect.equals(string, dart.toString(s));
+          async_helper$.asyncEnd();
+        }, dynamicAnddynamicTodynamic())});
+      c.addError(0, stringTrace);
+      c.close();
+    }, dynamicTodynamic()));
+  };
+  dart.fn(stacktrace_fromstring_test.main, VoidTovoid());
+  // Exports:
+  exports.stacktrace_fromstring_test = stacktrace_fromstring_test;
+});