Add test for cache delete

sentry-rails/spec/sentry/rails/tracing/active_support_subscriber_spec.rb

@@ -144,6 +144,22 @@
       expect(cache_transaction[:spans][1][:data]['cache.key']).to eq(["my_cache_key_non_existing"])
       expect(cache_transaction[:spans][1][:data]['cache.hit']).to eq(false)
     end
+
+    it "tracks cache delete" do
+      Rails.cache.write("my_cache_key", "my_cache_value")
+      transaction = Sentry::Transaction.new(sampled: true, hub: Sentry.get_current_hub)
+      Sentry.get_current_scope.set_span(transaction)
+      Rails.cache.delete("my_cache_key")
+
+      transaction.finish
+      expect(transport.events.count).to eq(1)
+      cache_transaction = transport.events.first.to_hash
+      expect(cache_transaction[:type]).to eq("transaction")
+      expect(cache_transaction[:spans].count).to eq(1)
+      expect(cache_transaction[:spans][0][:op]).to eq("cache.remove")
+      expect(cache_transaction[:spans][0][:origin]).to eq("auto.cache.rails")
+      expect(cache_transaction[:spans][0][:data]['cache.key']).to eq(["my_cache_key"])
+    end
   end
 
   context "when transaction is not sampled" do