Expect.js Examples

Question 1

expect(1).to.be.ok();

Answer 1

Expect the 1 to be truthy.

Question 2

expect({}).to.be.ok();

Answer 2

Expects {} to be truthy.

Question 3

expect(0).to.not.be.ok();

Answer 3

Expects 0 to be falsy.

Question 4

expect(1).to.be(1)

Answer 4

Expect 1 === 1

Question 5

expect(NaN).not.to.equal(NaN);

Answer 5

Expects NaN === NaN

Question 6

expect({ a: ‘b’ }).to.eql({ a: ‘b’ });

Answer 6

Expects two objects to have the same key values.

Question 7

expect(5).to.be.a(‘number’);

Answer 7

Expects a value of 5 to be of type ‘Number’

Question 8

expect([ ‘dog’, ‘cat; ]).to.be.an(‘array’);

Answer 8

Expects value to be of type ‘Array’.

Question 9

expect([ ‘dog’, ‘cat’ ] ).to.be.an(‘object’);

Answer 9

Expects the type object, using TypeOf Command.

Question 10

expect(5).to.be.a(Number);

Answer 10

Expects 5 to be a Contructor Number

Question 11

expect(program.version).to.match(/[0-9]+.[0-9]+.[0-9]+/);

Answer 11

Expects the program.version to match a regex of #.#.#.

Question 12

expect([1, 2]).to.contain(1);

Answer 12

Expectes to find a value 1 in an array of [ 1, 2 ]

Question 13

expect(‘hello world’).to.contain(‘world’);

Answer 13

Expects a string to ‘Hello World’ to contain the substring ‘world’.

Question 14

expect([1,2,3]).to.have.length(3);

Answer 14

Expects an array to have three elements.

Question 15

expect([]).to.be.empty();

Answer 15

Expects to find an array with no elements.

Question 16

expect({}).to.be.empty();

Answer 16

Expects to find an object with no key value pairs.

Question 17

expect({ my: ‘object’ }).to.not.be.empty();`

Answer 17

Expects an object to NOT be empty.

Question 18

expect({a: ‘b’}).to.have.property(‘a’);

Answer 18

Expects a object to have a key of ‘a’.

Question 19

expect({ a: ‘b’, c: ‘d’ }).to.only.have.keys(‘a’, ‘c’);

Answer 19

Expects an object to have only keys ‘a’ and ‘b’.

Question 20

expect({ a: ‘b’, c: ‘d’ }).to.not.only.have.key(‘a’);

Answer 20

Expects an object to not only have a key of ‘a’. There must be more keys for this to be true.

Question 21

expect(1).to.be.within(0, Infinity);

Answer 21

Expects a number that falls between the range of 1 and Infinity.

Question 22

expect(5).to.be.greaterThan(3);

Answer 22

Expects a number (5) to be greater then a number (3).

Question 23

expect(1).to.be.lessThan(3);

Answer 23

Expects the number (1) to be less Then the number (3).