Copy the Title and first paragraph of the hub you are testing. Paste this into your search engine. Your hub should be the first and ONLY one with ALL these words in it. If you see another one there then click on the url and it will bring you to the the site that has stolen your content.
It depends on how long your paragraphs are, I usually copy around 50 to 60 words and the Title and then hold my breath hoping I do not find any thefts. If you published any hubs since March then they have likely been stolen by that site that every one is talking about here at HubPages