Add a Pub validator for READMEs that are invalid utf-8.

utils/tests/pub/validator_test.dart

Index: utils/tests/pub/validator_test.dart
diff --git a/utils/tests/pub/validator_test.dart b/utils/tests/pub/validator_test.dart
index cc89c62a75616438f9d8de82603ee78ef542d797..bc4e30e4fa2f6662ff9ed229a460fbcb7ff074e3 100644
--- a/utils/tests/pub/validator_test.dart
+++ b/utils/tests/pub/validator_test.dart
@@ -22,6 +22,7 @@ import '../../pub/validator/lib.dart';
 import '../../pub/validator/license.dart';
 import '../../pub/validator/name.dart';
 import '../../pub/validator/pubspec_field.dart';
+import '../../pub/validator/utf8_readme.dart';
 
 void expectNoValidationError(ValidatorCreator fn) {
   expectLater(schedulePackageValidation(fn), pairOf(isEmpty, isEmpty));
@@ -53,6 +54,9 @@ Validator name(Entrypoint entrypoint) => new NameValidator(entrypoint);
 Validator pubspecField(Entrypoint entrypoint) =>
   new PubspecFieldValidator(entrypoint);
 
+Validator utf8Readme(Entrypoint entrypoint) =>
+  new Utf8ReadmeValidator(entrypoint);
+
 void scheduleNormalPackage() => normalPackage.scheduleCreate();
 
 main() {
@@ -141,6 +145,14 @@ main() {
       ]).scheduleCreate();
       expectNoValidationError(compiledDartdoc);
     });
+
+    integration('has a non-primary readme with invalid utf-8', () {
+      dir(appPath, [
+        file("README", "Valid utf-8"),
+        binaryFile("README.invalid", [192])
+      ]).scheduleCreate();
+      expectNoValidationError(utf8Readme);
+    });
   });
 
   group('should consider a package invalid if it', () {
@@ -550,5 +562,12 @@ main() {
 
       expectValidationWarning(compiledDartdoc);
     });
+
+    test('has a README with invalid utf-8', () {
+      dir(appPath, [
+        binaryFile("README", [192])
+      ]).scheduleCreate();
+      expectValidationWarning(utf8Readme);
+    });
   });
 }