Wear Black?

I have a friend who has asked me to be an honorary bridesmaid at her wedding next weekend. It`s at 4pm. The bridesmaid dresses are a dark wine with black trim on the sleeves. Does anyone have a suggestion on what I should wear. Some people have told me to wear a summery black dress with strappy sandals. However, I thought it was bad etiquette to wear black to a wedding. I would like to coordinate with everyone else so I won`t stand out, however, I don`t know what the other honoraries are wearing. Please help if you have a suggestion. Also, does anyone know what the responsibilities are for an honorary bridesmaid? I have never heard of the title. Thanks for helping!