{
  "exercise": "list-ops",
  "version": "1.0.0",
  "comments": [
    "Though there are no specifications here for dealing with large lists,",
    "implementers may add tests for handling large lists to ensure that the",
    "solutions have thought about performance concerns."
  ],
  "cases": [
    {
      "description": "append entries to a list and return the new list",
      "cases": [
        {
          "description": "empty lists",
          "property": "append",
          "list1": [],
          "list2": [],
          "expected": []
        },
        {
          "description": "empty list to list",
          "property": "append",
          "list1": [],
          "list2": [1, 2, 3, 4],
          "expected": [1, 2, 3, 4]
        },
        {
          "description": "non-empty lists",
          "property": "append",
          "list1": [1, 2],
          "list2": [2, 3, 4, 5],
          "expected": [1, 2, 2, 3, 4, 5]
        }
      ]
    },
    {
      "description": "concat lists and lists of list into a new list",
      "cases": [
        {
          "description": "empty list",
          "property": "concat",
          "lists": [],
          "expected": []
        },
        {
          "description": "list of lists",
          "property": "concat",
          "lists": [[1, 2], [3], [], [4, 5, 6]],
          "expected": [1, 2, 3, 4, 5, 6]
        }
      ]
    },
    {
      "description": "filter list returning only values that satisfy the filter function",
      "cases": [
        {
          "description": "empty list",
          "property": "filter",
          "list": [],
          "function": "value modulo 2 == 1",
          "expected": []
        },
        {
          "description": "non-empty list",
          "property": "filter",
          "list": [1, 2, 3, 5],
          "function": "value modulo 2 == 1",
          "expected": [1, 3, 5]
        }
      ]
    },
    {
      "description": "returns the length of a list",
      "cases": [
        {
          "description": "empty list",
          "property": "length",
          "list": [],
          "expected": 0
        },
        {
          "description": "non-empty list",
          "property": "length",
          "list": [1, 2, 3, 4],
          "expected": 4
        }
      ]
    },
    {
      "description": "return a list of elements whos values equal the list value transformed by the mapping function",
      "cases": [
        {
          "description": "empty list",
          "property": "map",
          "list": [],
          "function": "value + 1",
          "expected": []
        },
        {
          "description": "non-empty list",
          "property": "map",
          "list": [1, 3, 5, 7],
          "function": "value + 1",
          "expected": [2, 4, 6, 8]
        }
      ]
    },
    {
      "description": "folds (reduces) the given list from the left with a function",
      "cases": [
        {
          "description": "empty list",
          "property": "foldl",
          "list": [],
          "initial": 2,
          "function": "value / accumulator",
          "expected": 2
        },
        {
          "description": "division of integers",
          "property": "foldl",
          "list": [1, 2, 3, 4],
          "initial": 24,
          "function": "value / accumulator",
          "expected": 64
        }
      ]
    },
    {
      "description": "folds (reduces) the given list from the right with a function",
      "cases": [
        {
          "description": "empty list",
          "property": "foldr",
          "list": [],
          "initial": 2,
          "function": "value / accumulator",
          "expected": 2
        },
        {
          "description": "division of integers",
          "property": "foldr",
          "list": [1, 2, 3, 4],
          "initial": 24,
          "function": "value / accumulator",
          "expected": 9
        }
      ]
    },
    {
      "description": "reverse the elements of the list",
      "cases": [
        {
          "description": "empty list",
          "property": "reverse",
          "list": [],
          "expected": []
        },
        {
          "description": "non-empty list",
          "property": "reverse",
          "list": [1, 3, 5, 7],
          "expected": [7, 5, 3, 1]
        }
      ]
    }
  ]
}