FIX: Cache url data for failed inline oneboxes

spec/components/inline_oneboxer_spec.rb

@@ -39,6 +39,21 @@ describe InlineOneboxer do
       expect(cached[:url]).to eq(topic.url)
       expect(cached[:title]).to eq(topic.title)
     end
+
+    it "puts an entry in the cache for failed onebox" do
+      SiteSetting.enable_inline_onebox_on_all_domains = true
+      url = "https://example.com/random-url"
+
+      expect(InlineOneboxer.cache_lookup(url)).to be_blank
+
+      result = InlineOneboxer.lookup(url)
+      expect(result).to be_present
+
+      cached = InlineOneboxer.cache_lookup(url)
+      expect(cached).to be_present
+      expect(cached[:url]).to eq(url)
+      expect(cached[:title]).to be_nil
+    end
   end
 
   context ".lookup" do