Unclear on how to use Format.toCsv(FakeCollection<T> collection)

[ghost]

This is neither a bug nor a feature request, that's why I'm writing in free form, I hope that's okay.

I'm trying to do the following:

1. Generate valid CSV data (using datafaker)
2. Give CSV string to a parser (the one under test)
3. Compare parsed entities with the generated CSV data

How could one go about doing this? I saw that there is a Format.toCSV() overload that accepts a collection but it's unclear to me how you'd use that method.

[bodiam]

No worries at all. I'm happy to help you more, but as a starting point, did you have a look at this documentation?

https://www.datafaker.net/documentation/file-formats/#csv

If so, is there anything specially unclear?

[ghost]

The documentation is a bit unclear on how to use a collection builder for generating CSV files. An example like the test shown here would have been nice:

datafaker/src/test/java/net/datafaker/FakeCollectionTest.java

Line 193 in 94d9955

void differentNumberOfHeadersAndColumns() {

.

I've basically done the following right now:

1. Create a custom class that has methods for each faked value (e.g. one for generating uuids, one for generating dates)
2. Create a custom faker that uses that custom class and initializes the Faker-superclass with the same random seed each time
3. Use two different custom faker instances: one builds a collection for comparing the parsed entities and the other one for generating the CSV file

I'd be willing to submit a PR if you'd like. Three PRs, actually. One explaining how to use a collection builder for generating CSV files, another one for an end-to-end example on how to compare the custom generated entities with domain objects. The third PR would have a certain nullRate to inject errors. What do you think?

I've also noticed that generating UUIDs ignores the Faker's random seed, thus generating a "truly" random UUID each time. What do you think of changing that? A simple hack could be to simply call UUID.nameUUIDFromBytes() and passing a randomly generated number each time, using the RandomService / user provided random seed.

Edit:

• I just saw that there CSV + Collections example in the README. Adding it to the main website would help out greatly
• Adding a internet().uuidv3() would perhaps works? Leaving the existing uuid() one unchanged.

[bodiam]

I really like all your ideas, and I'd accept any PR if you'd be willing to submit one. Thanks for the great feedback, that's really useful!

[ghost]

No problem, will do. Would you like me to create new issues for all the things I've just mentioned or shall I simply reference this issue in each PR?

[snuyanzin]

just fyi: there is also a separate doc about collections https://www.datafaker.net/documentation/collections/
may be the issue is missing link between collection's and csv's doc pages?

[bodiam]

No problem, will do. Would you like me to create new issues for all the things I've just mentioned or shall I simply reference this issue in each PR?

Thanks again! And I have no preference, whatever works best for you.

[ghost]

just fyi: there is also a separate doc about collections https://www.datafaker.net/documentation/collections/ may be the issue is missing link between collection's and csv's doc pages?

Basically, yes.

[ghost]

I can't think of another good documentation example and the uuid randomness issue has been fixed, I'll close this issue.