Store actual Reference(s) for additional exports.

pkg/front_end/test/src/incremental/kernel_driver_test.dart

Index: pkg/front_end/test/src/incremental/kernel_driver_test.dart
diff --git a/pkg/front_end/test/src/incremental/kernel_driver_test.dart b/pkg/front_end/test/src/incremental/kernel_driver_test.dart
index f4de69e90973955076e8f452fa32414ce5f50d5d..d495e47c31dc44781e3c8cc3fd92e56d60a8418d 100644
--- a/pkg/front_end/test/src/incremental/kernel_driver_test.dart
+++ b/pkg/front_end/test/src/incremental/kernel_driver_test.dart
@@ -108,15 +108,31 @@ static method main() → void {}
     String aPath = '/test/lib/a.dart';
     String bPath = '/test/lib/b.dart';
     String cPath = '/test/lib/c.dart';
+    String dPath = '/test/lib/d.dart';
     writeFile(aPath, 'class A {}');
-    writeFile(bPath, 'export "a.dart";');
-    Uri cUri = writeFile(cPath, r'''
-import 'b.dart';
+    Uri bUri = writeFile(bPath, 'export "a.dart";');
+    Uri cUri = writeFile(cPath, 'export "b.dart";');
+    Uri dUri = writeFile(dPath, r'''
+import 'c.dart';
 A a;
 ''');
 
-    KernelResult result = await driver.getKernel(cUri);
-    Library library = _getLibrary(result, cUri);
+    KernelResult result = await driver.getKernel(dUri);
+    Library library = _getLibrary(result, dUri);
+    expect(_getLibraryText(_getLibrary(result, bUri)), r'''
+library;
+import self as self;
+import "./a.dart" as a;
+additionalExports = (a::A)
+
+''');
+    expect(_getLibraryText(_getLibrary(result, cUri)), r'''
+library;
+import self as self;
+import "./a.dart" as a;
+additionalExports = (a::A)
+
+''');
     expect(_getLibraryText(library), r'''
 library;
 import self as self;