diff --git a/Gemfile b/Gemfile
index 1aef4acc1..92332c2e6 100644
--- a/Gemfile
+++ b/Gemfile
@@ -86,4 +86,5 @@ group :test do
   gem "capybara"
   gem "selenium-webdriver"
   gem "codecov", require: false
+  gem 'stripe-ruby-mock', require: "stripe_mock"
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index e93fe7071..1bab4040e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -134,6 +134,7 @@ GEM
     concurrent-ruby (1.1.7)
     crass (1.0.6)
     daemons (1.3.1)
+    dante (0.2.0)
     delayed_job (4.1.8)
       activesupport (>= 3.0, < 6.1)
     delayed_job_active_record (4.1.4)
@@ -354,6 +355,10 @@ GEM
     streamio-ffmpeg (3.0.2)
       multi_json (~> 1.8)
     stripe (5.28.0)
+    stripe-ruby-mock (3.0.1)
+      dante (>= 0.2.0)
+      multi_json (~> 1.0)
+      stripe (> 5, < 6)
     thor (1.0.1)
     thread_safe (0.3.6)
     tzinfo (1.2.8)
@@ -452,6 +457,7 @@ DEPENDENCIES
   stackprof
   streamio-ffmpeg
   stripe
+  stripe-ruby-mock
   unicorn
   unicorn-worker-killer
   webpacker (>= 4.0.x)
diff --git a/app/controllers/user_upgrades_controller.rb b/app/controllers/user_upgrades_controller.rb
index 903f7b6ec..be7ee116a 100644
--- a/app/controllers/user_upgrades_controller.rb
+++ b/app/controllers/user_upgrades_controller.rb
@@ -42,15 +42,10 @@ class UserUpgradesController < ApplicationController
     end
 
     begin
-      charge = Stripe::Charge.create(
-        :amount => cost,
-        :currency => "usd",
-        :card => params[:stripeToken],
-        :description => params[:desc]
-      )
+      charge = Stripe::Charge.create(amount: cost, currency: "usd", source: params[:stripeToken], description: params[:desc])
       @user.promote_to!(level, User.system, is_upgrade: true)
       flash[:success] = true
-    rescue Stripe::CardError => e
+    rescue Stripe::StripeError => e
       DanbooruLogger.log(e)
       flash[:error] = e.message
     end
diff --git a/test/functional/user_upgrades_controller_test.rb b/test/functional/user_upgrades_controller_test.rb
index b4450f8a1..8fbd64d34 100644
--- a/test/functional/user_upgrades_controller_test.rb
+++ b/test/functional/user_upgrades_controller_test.rb
@@ -1,6 +1,14 @@
 require 'test_helper'
 
 class UserUpgradesControllerTest < ActionDispatch::IntegrationTest
+  setup do
+    StripeMock.start
+  end
+
+  teardown do
+    StripeMock.stop
+  end
+
   context "The user upgrades controller" do
     context "new action" do
       should "render" do
@@ -15,5 +23,97 @@ class UserUpgradesControllerTest < ActionDispatch::IntegrationTest
         assert_response :success
       end
     end
+
+    context "create action" do
+      setup do
+        @user = create(:user)
+        @token = StripeMock.generate_card_token
+      end
+
+      context "a self upgrade" do
+        should "upgrade a Member to Gold" do
+          post_auth user_upgrade_path, @user, params: { stripeToken: @token, desc: "Upgrade to Gold" }
+
+          assert_redirected_to user_upgrade_path
+          assert_equal(true, @user.reload.is_gold?)
+        end
+
+        should "upgrade a Member to Platinum" do
+          post_auth user_upgrade_path, @user, params: { stripeToken: @token, desc: "Upgrade to Platinum" }
+
+          assert_redirected_to user_upgrade_path
+          assert_equal(true, @user.reload.is_platinum?)
+        end
+
+        should "upgrade a Gold user to Platinum" do
+          @user.update!(level: User::Levels::GOLD)
+          post_auth user_upgrade_path, @user, params: { stripeToken: @token, desc: "Upgrade Gold to Platinum" }
+
+          assert_redirected_to user_upgrade_path
+          assert_equal(true, @user.reload.is_platinum?)
+        end
+
+        should "log an account upgrade modaction" do
+          assert_difference("ModAction.user_account_upgrade.count") do
+            post_auth user_upgrade_path, @user, params: { stripeToken: @token, desc: "Upgrade to Gold" }
+          end
+        end
+
+        should "send the user a dmail" do
+          assert_difference("@user.dmails.received.count") do
+            post_auth user_upgrade_path, @user, params: { stripeToken: @token, desc: "Upgrade to Gold" }
+          end
+        end
+      end
+
+      context "a gifted upgrade" do
+        should "upgrade the user to Gold" do
+          @other_user = create(:user)
+          post_auth user_upgrade_path, @user, params: { stripeToken: @token, desc: "Upgrade to Gold", user_id: @other_user.id }
+
+          assert_redirected_to user_upgrade_path(user_id: @other_user.id)
+          assert_equal(true, @other_user.reload.is_gold?)
+          assert_equal(false, @user.reload.is_gold?)
+        end
+      end
+
+      context "an upgrade with a missing Stripe token" do
+        should "not upgrade the user" do
+          post_auth user_upgrade_path, @user, params: { desc: "Upgrade to Gold" }
+
+          assert_response :success
+          assert_equal(true, @user.reload.is_member?)
+        end
+      end
+
+      context "an upgrade with an invalid Stripe token" do
+        should "not upgrade the user" do
+          post_auth user_upgrade_path, @user, params: { stripeToken: "garbage", desc: "Upgrade to Gold" }
+
+          assert_redirected_to user_upgrade_path
+          assert_equal(true, @user.reload.is_member?)
+        end
+      end
+
+      context "an upgrade with an credit card that is declined" do
+        should "not upgrade the user" do
+          StripeMock.prepare_card_error(:card_declined)
+          post_auth user_upgrade_path, @user, params: { stripeToken: @token, desc: "Upgrade to Gold" }
+
+          assert_redirected_to user_upgrade_path
+          assert_equal(true, @user.reload.is_member?)
+        end
+      end
+
+      context "an upgrade with an credit card that is expired" do
+        should "not upgrade the user" do
+          StripeMock.prepare_card_error(:expired_card)
+          post_auth user_upgrade_path, @user, params: { stripeToken: @token, desc: "Upgrade to Gold" }
+
+          assert_redirected_to user_upgrade_path
+          assert_equal(true, @user.reload.is_member?)
+        end
+      end
+    end
   end
 end