Revert "Remove Expect from core library."

tests/standalone/package/package_test.dart

Index: tests/standalone/package/package_test.dart
diff --git a/tests/standalone/package/package_test.dart b/tests/standalone/package/package_test.dart
index b606a23812f34fa745211053f62e195809821472..e55181a7467460338434a70b328e8d506185341d 100644
--- a/tests/standalone/package/package_test.dart
+++ b/tests/standalone/package/package_test.dart
@@ -4,10 +4,10 @@
 
 // PackageRoot=none
 
-library package_test;
+#library('package_test');
 
-import 'package:lib1.dart';
-import 'package:shared.dart';
+#import('package:lib1.dart');
+#import('package:shared.dart');
 
 void main() {
   output = 'main';
@@ -15,7 +15,5 @@ void main() {
   lib1();
 
   // Make sure they were all reached successfully.
-  if (output != 'main|lib1|lib2|lib3') {
-    throw new Error("libraries were not reached successfully");
-  }
+  Expect.equals(output, 'main|lib1|lib2|lib3');
 }