Because your code does something very clever but your stakeholders don't have a clue how to read Scala!
Scenario: Read data from CSV files, join and save it to parquet
Given a file called "housePrices.csv" containing
"""
318000,NN9 6LS,D
137000,NN3 8HJ,T
180000,NN14 6TN,S
249000,NN14 6TN,D
"""
And a file called "postcodes.csv" containing
"""
NN9 6LS,51.1,-1.2
NN3 8HJ,51.2,-1.1
NN14 6TN,51.3,-1.0
"""
When I read the data from "housePrices.csv" and "postcodes.csv" join then save to parquet
Then the parquet data written to "results.parquet" is
| Price:Int | Postcode:String | HouseType:String | Latitude:Double | Longitude:Double |
| 318000 | NN9 6LS | D | 51.1 | -1.2 |
| 137000 | NN3 8HJ | T | 51.2 | -1.1 |
| 180000 | NN14 6TN | S | 51.3 | -1.0 |
| 249000 | NN14 6TN | D | 51.3 | -1.0 |