Edge-case injection

Testing the happy path is the easy part. Ask for the values that break parsers: unicode names, emoji, RTL text, empty strings, boundary numerics, nulls in nullable columns.

synth.New(synth.WithChaos(0.02))   // 2% of records carry a nasty value

From the CLI:

synth gen -s users.yaml -n 100000 --chaos 0.02 -o users.csv

The fraction is between 0 and 1. Chaos is seeded like everything else, so a parser that fell over on run 4,231 falls over there again.