diff --git a/spec/googleauth/compute_engine_spec.rb b/spec/googleauth/compute_engine_spec.rb
index 209fb12..5b5ba06 100644
--- a/spec/googleauth/compute_engine_spec.rb
+++ b/spec/googleauth/compute_engine_spec.rb
@@ -44,7 +44,8 @@ describe Google::Auth::GCECredentials do
     @client = GCECredentials.new
   end
 
-  def make_auth_stubs(access_token: '')
+  def make_auth_stubs(opts = {})
+    access_token = opts[:access_token] || ''
     Faraday::Adapter::Test::Stubs.new do |stub|
       stub.get(MD_URI) do |env|
         headers = env[:request_headers]
diff --git a/spec/googleauth/service_account_spec.rb b/spec/googleauth/service_account_spec.rb
index e6657b4..f0ec305 100644
--- a/spec/googleauth/service_account_spec.rb
+++ b/spec/googleauth/service_account_spec.rb
@@ -50,7 +50,8 @@ describe Google::Auth::ServiceAccountCredentials do
         StringIO.new(cred_json_text))
   end
 
-  def make_auth_stubs(access_token: '')
+  def make_auth_stubs(opts = {})
+    access_token = opts[:access_token] || ''
     Faraday::Adapter::Test::Stubs.new do |stub|
       stub.post('/oauth2/v3/token') do |env|
         params = Addressable::URI.form_unencode(env[:body])
diff --git a/spec/googleauth/signet_spec.rb b/spec/googleauth/signet_spec.rb
index 09bb24b..de02d16 100644
--- a/spec/googleauth/signet_spec.rb
+++ b/spec/googleauth/signet_spec.rb
@@ -49,7 +49,8 @@ describe Signet::OAuth2::Client do
       )
   end
 
-  def make_auth_stubs(access_token: '')
+  def make_auth_stubs(opts)
+    access_token = opts[:access_token] || ''
     Faraday::Adapter::Test::Stubs.new do |stub|
       stub.post('/o/oauth2/token') do |env|
         params = Addressable::URI.form_unencode(env[:body])