Use expect for nested params in more controllers (#33675)

spec/requests/disputes/appeals_spec.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe 'Disputes Appeals' do
+  describe 'POST /disputes/appeals' do
+    before { sign_in strike.target_account.user }
+
+    let(:strike) { Fabricate :account_warning }
+
+    it 'gracefully handles invalid nested params' do
+      post disputes_strike_appeal_path(strike, appeal: 'invalid')
+
+      expect(response)
+        .to have_http_status(400)
+    end
+  end
+end