Use single quotes for identifiers

test/modules/types/message_test.js

@@ -246,14 +246,14 @@ describe('Message', () => {
       const toVersionX = () => {};
       assert.throws(
         () => Message._withSchemaVersion(toVersionX, 2),
-        '"schemaVersion" is invalid'
+        "'schemaVersion' is invalid"
       );
     });
 
     it('should require an upgrade function', () => {
       assert.throws(
         () => Message._withSchemaVersion(2, 3),
-        '"upgrade" must be a function'
+        "'upgrade' must be a function"
       );
     });