Clean up handling of types.

tests/utils/src/DummyCompilerTest.dart

Index: tests/utils/src/DummyCompilerTest.dart
diff --git a/tests/utils/src/DummyCompilerTest.dart b/tests/utils/src/DummyCompilerTest.dart
index 20155cc6e77af1e2b1f3825d8ad7218b7d8b52c3..a5e85a0aad4cf2ad715e2dac4b9e682377fa7bf6 100644
--- a/tests/utils/src/DummyCompilerTest.dart
+++ b/tests/utils/src/DummyCompilerTest.dart
@@ -12,8 +12,25 @@ Future<String> provider(Uri uri) {
   String source;
   if (uri.scheme == "main") {
     source = "main() {}";
+  } else if (uri.scheme == "lib") {
+    if (uri.path.endsWith("/core.dart")) {
+      source = """#library('core');
+                  class Object{}
+                  class bool {}
+                  class num {}
+                  class int {}
+                  class double{}
+                  class String{}
+                  class Function{}
+                  class List {}
+                  class Closure {}
+                  class Dynamic {}
+                  class Null {}""";
+    } else {
+      source = "#library('lib');";
+    }
   } else {
-    source = "#library('lib');";
+   throw "unexpected URI $uri";
   }
   completer.complete(source);
   return completer.future;