contains.test.js

const contains = require("./contains.js");

/*
Implement a function called contains that checks an object contains a
particular property

E.g. contains({a: 1, b: 2}, 'a') // returns true
as the object contains a key of 'a'

E.g. contains({a: 1, b: 2}, 'c') // returns false
as the object doesn't contains a key of 'c'
*/

// Acceptance criteria:

// Given a contains function
// When passed an object and a property name
// Then it should return true if the object contains the property, false otherwise

// Given an empty object
// When passed to contains
// Then it should return false

// Given an object with properties
// When passed to contains with an existing property name
// Then it should return true

// Given an object with properties
// When passed to contains with a non-existent property name
// Then it should return false

// Given invalid parameters like an array
// When passed to contains
// Then it should return false or throw an error

describe("contains", () => {
  [
    { input: [{}, "a"], expected: false },
    { input: [{ a: 1, b: 2 }, "a"], expected: true },
    { input: [{ a: 1, b: 2 }, "c"], expected: false },
    { input: [null, "a"], expected: false },
  ].forEach(({ input, expected }) =>
    it(`return if object contains the key for ${input[1]}`, () =>
      expect(contains(...input)).toEqual(expected))
  );
});