[MAINTENANCE] Remaining integration tests around GXValidateCheckpointOperator

[tyler-hoffman]

Adds remaining integration tests around GXValidateCheckpointOperator.

The approach

• 1 test per context type
• 1 test per category of data source (sql, file system, data frame)

New stuff

• Light-weight fixture for writing csv files
• Splits apart the checkpoint configuration fixture so that one fixture creates the checkpoint, and one knows about cleaning it up, since that's only relevant to cloud
• More comments

Where this strays from the light
CORE 728 says "Cloud tests should ensure that the validation result can be retrieved from the cloud backend.", but a) our API for that doesn't work, and b) that's testing gx cloud itself, not our interactions with it via the operator, so I think it's fine and reasonable to skip that.

[joshua-stauffer]

thanks, this looks great, and i agree with your assessment that we don't need to actually pull results from cloud. I would like to make sure we're giving the user a path to retrieve them. Could we assert (in this PR or in a followup) that the user receives the results_url in the operator return value?

[tyler-hoffman]

thanks, this looks great, and i agree with your assessment that we don't need to actually pull results from cloud. I would like to make sure we're giving the user a path to retrieve them. Could we assert (in this PR or in a followup) that the user receives the results_url in the operator return value?

yeah good call. ff24119 adds a rough assertion on this.