public void CanAddSubgroup()
 {
     using(EF_ZMT_DbContext.EF_ZMT_DbContext context = new EF_ZMT_DbContext.EF_ZMT_DbContext())
     {
         FixedAssetService transaction = new FixedAssetService();
         context.Context.ExecuteStoreCommand("DELETE FROM Subgroup");
         Subgroup subgroup = new Subgroup() { name = "Środki wysokiej wartości", short_name = "N491" };
         transaction.AddSubgroup(subgroup);
         Assert.AreEqual(context.Context.Subgroups.Count(), 1);
         subgroup = context.Context.Subgroups.FirstOrDefault(x => x.short_name == "N491");
         Assert.IsNotNull(subgroup);
         Assert.AreEqual(subgroup.name, "Środki wysokiej wartości");
     }
 }