Erh, gothenburg metal shop?
You mean the Metaltown one day festival?
It's on the 7th of july and Opeth, Tool, Motorhead, Soilwork, Cradle of Filth, Danko Jones, The Haunted, Entombed, Khoma, Evergay and Engel will play. Not sure if they will annouce more bands later on, probably smaller acts in that case. Last year they had two larger outdoor stages and one smaller indoors.
The festival is held at a pier in the Gothenburg marina, just a few minutes from the central station by the tram/bus.
Think you should go if you can as it probably will be nice. Just hope it won't constantly rain this year
The tickets are around 52 euro.
More info here:
http://www.metaltown.se/