data:
    - {_id: 1, x: 11}
    - {_id: 2, x: 22}
    - {_id: 3, x: 33}

tests:
    -
        description: "Distinct without a filter"
        operation:
            name: distinct
            arguments:
                fieldName: "x"
                filter: {}

        outcome:
            result: 
                - 11
                - 22
                - 33
    -
        description: "Distinct with a filter"
        operation:
            name: distinct
            arguments:
                fieldName: "x"
                filter: 
                    _id: {$gt: 1}

        outcome:
            result: 
                - 22
                - 33