Fix auth using header

modules/__tests__/utils/withAuthHeader.js

@@ -0,0 +1,13 @@
+const withToken = require("./withToken");
+
+function encodeBase64(token) {
+  return Buffer.from(token).toString("base64");
+}
+
+function withAuthHeader(scopes, done) {
+  withToken(scopes, token => {
+    done(encodeBase64(token));
+  });
+}
+
+module.exports = withAuthHeader;