Search code examples
c#filehelpers

Testing error handling when writing a csv file

I would like to set ErrorMode = ErrorMode.SaveAndContinue so I can process errors after a CSV file has been written.

How can I generate row level errors artificially when calling WriteStream() so that I can test my error handling?

In particular I would like to find out whether the AfterWriteRecord event is fired if a row errors.

Solution

  • Looking at the source code there are a few ways:

    You call WriteStream() with an IEnumerable<T> where T is your FileHelpers record class. So in your test, create a List<T>, but add null to it as one of the records. This will cause WriteStream() to raise a BadUsageException.

    Alternatively, you could add an OnProgress event in which you throw an exception.

    You could also throw an exception from a BeforeWriteEvent or an AfterWriteEvent.

    You could attach a custom field converter which throws an exception in the FieldToString() override.

    Any of the above exceptions will be trapped by the SaveAndContinue option.