diff --git a/OPENAPI_VERSION b/OPENAPI_VERSION
index d377f60a..2b4f3461 100644
--- a/OPENAPI_VERSION
+++ b/OPENAPI_VERSION
@@ -1 +1 @@
-v154
\ No newline at end of file
+v157
\ No newline at end of file
diff --git a/lib/stripe/resources/customer.rb b/lib/stripe/resources/customer.rb
index 7690f19c..a6645213 100644
--- a/lib/stripe/resources/customer.rb
+++ b/lib/stripe/resources/customer.rb
@@ -146,5 +146,31 @@ module Stripe
         opts: opts
       )
     end
+
+    def test_helpers
+      TestHelpers.new(self)
+    end
+
+    class TestHelpers < APIResourceTestHelpers
+      RESOURCE_CLASS = Customer
+
+      def self.fund_cash_balance(customer, params = {}, opts = {})
+        request_stripe_object(
+          method: :post,
+          path: format("/v1/test_helpers/customers/%<customer>s/fund_cash_balance", { customer: CGI.escape(customer) }),
+          params: params,
+          opts: opts
+        )
+      end
+
+      def fund_cash_balance(params = {}, opts = {})
+        @resource.request_stripe_object(
+          method: :post,
+          path: format("/v1/test_helpers/customers/%<customer>s/fund_cash_balance", { customer: CGI.escape(@resource["id"]) }),
+          params: params,
+          opts: opts
+        )
+      end
+    end
   end
 end
diff --git a/test/stripe/generated_examples_test.rb b/test/stripe/generated_examples_test.rb
index fffc1872..f2344ae8 100644
--- a/test/stripe/generated_examples_test.rb
+++ b/test/stripe/generated_examples_test.rb
@@ -409,6 +409,15 @@ module Stripe
         assert_requested :delete, "#{Stripe.api_base}/v1/customers/cus_xxxxxxxxxxxxx?"
       end
     end
+    context "Customer.fund_cash_balance" do
+      should "support requests with args: customer, amount, currency" do
+        Stripe::Customer::TestHelpers.fund_cash_balance(
+          "cus_123",
+          { amount: 30, currency: "eur" }
+        )
+        assert_requested :post, "#{Stripe.api_base}/v1/test_helpers/customers/cus_123/fund_cash_balance"
+      end
+    end
     context "Customer.list" do
       should "support requests with args: limit" do
         Stripe::Customer.list(limit: 3)