public void WhenDiskQuotaUsedFails_ReturnZero() { var quota = Substitute.For <DIDiskQuotaUser>(); this.DiskQuotaControl.FindUser(User.SID).Returns(quota); quota.QuotaUsed.Throws(new System.Runtime.InteropServices.COMException()); Assert.Equal(0ul, Container.CurrentDiskUsage()); }