How to test async function with Unit test

Question

I have a function code like this:

        public static async Task<bool> RemoveUnitFile(string unitType)
        {
            if (!unitType.ToLower().EndsWith(".xml"))
            {
                unitType = unitType + ".xml";
            }
            StorageFolder local = ApplicationData.Current.LocalFolder;
            try
            {
                StorageFile file = await local.GetFileAsync(unitType);
                await file.DeleteAsync();
                return true;
            }
            catch
            {
                return false;
            }
        }

And I'm trying to create a Unit Test function:

        [TestMethod]
        public async void TestDeleteFile()
        {
            Assert.IsTrue(await DataAccess.RemoveUnitFile("Units"));
        }

But after I build the Test project, the test method TestDeleteFile is not exist in the test explorer, how can I test the async functions??