public async Task Save_ShouldSaveTheXmlFile()
{
var fileName = @"CompleteSmellyFoo.xml";
XamlOnDiskLedgerBookRepository subject = CreateSubject();
var testData = LedgerBookTestData.TestData2();
await subject.SaveAsync(testData, fileName, false);
this.mockReaderWriter.Verify(m => m.WriteToDiskAsync(It.IsAny<string>(), It.IsAny<string>()));
}