private void VerifyExportErrorString(IConversation conversation, Exception ex, string descriptionExpected)
        {
            ExportError exportError = new ExportError(conversation, ex);
            var mockDescriptionHelper = new Mock<IConversationDescriptionHelper>();

            mockDescriptionHelper.Setup(x => x.GetDescription(It.IsAny<IConversation>()))
                .Returns("<some conversation>");

            ExportErrorFormatter errorFormatter = new ExportErrorFormatter(mockDescriptionHelper.Object);
            string descriptionActual = errorFormatter.Format(exportError);
            Assert.AreEqual(descriptionExpected, descriptionActual);
        }