Remove manual promotion code test (stripe#1691)

* removed promotion_code_test.rb (will be fully tested by generated_examples_test)

* regenerated generated_examples_test.rb

Author: jar-stripe

test/stripe/generated_examples_test.rb

@@ -3843,13 +3843,34 @@ class CodegennedExampleTest < Test::Unit::TestCase
       assert_requested :get, "#{Stripe::DEFAULT_API_BASE}/v1/promotion_codes/promo_xxxxxxxxxxxxx"
     end
     should "Test promotion codes post" do
+      promotion_code = Stripe::PromotionCode.create({
+        promotion: {
+          type: "coupon",
+          coupon: "Z4OV52SU",
+        },
+      })
+      assert_requested :post, "#{Stripe.api_base}/v1/promotion_codes"
+    end
+    should "Test promotion codes post (service)" do
+      stub_request(:post, "#{Stripe::DEFAULT_API_BASE}/v1/promotion_codes").to_return(body: "{}")
+      client = Stripe::StripeClient.new("sk_test_123")
+
+      promotion_code = client.v1.promotion_codes.create({
+        promotion: {
+          type: "coupon",
+          coupon: "Z4OV52SU",
+        },
+      })
+      assert_requested :post, "#{Stripe::DEFAULT_API_BASE}/v1/promotion_codes"
+    end
+    should "Test promotion codes post 2" do
       promotion_code = Stripe::PromotionCode.update(
         "promo_xxxxxxxxxxxxx",
         { metadata: { order_id: "6735" } }
       )
       assert_requested :post, "#{Stripe.api_base}/v1/promotion_codes/promo_xxxxxxxxxxxxx"
     end
-    should "Test promotion codes post (service)" do
+    should "Test promotion codes post 2 (service)" do
       stub_request(
         :post,
         "#{Stripe::DEFAULT_API_BASE}/v1/promotion_codes/promo_xxxxxxxxxxxxx"