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

describe("contains", () => {
// Given an empty object
// When passed to contains
// Then it should return false
it("contains on empty object returns false", () => {
    const object = {};
    const property = 'a'
    expect(contains(object, property)).toEqual(false)
});

// Given an object with properties
// When passed to contains with an existing property name
// Then it should return true
it("object contains property returns true", () => {
    const object = {a: 1, b: 2};
    const property = 'a'
    expect(contains(object, property)).toEqual(true)
});

// Given an object with properties
// When passed to contains with a non-existent property name
// Then it should return false
it("object does not contain property returns false", () => {
    const object = {a: 1, b: 2};
    const property = 'c'
    expect(contains(object, property)).toEqual(false)
});

// Given invalid parameters like an array
// When passed to contains
// Then it should return false or throw an error
it("given invalid parameter (an array) returns false or throws an error", () => {
    const object = [];
    const property = [];
    expect(contains(object, property)).toEqual(false)
});
});