Calculator testing

We are going to put our testing skills to the test(pun intended) by writing some tests on an existing piece of code.

Within testing_homework.js, we have a calculator object, along with some starter testing code, so far we have one test already, which tests the calculator.add() function, let's finish the rest of the tests!

Directions

1. Write an it() test for every method within calculator
2. If there are any bugs( there are :) ) fix them on the calculator object.
3. Make sure all of your tests that you write are correct.
4. Make all of your tests pass.

BONUS:
Fill out the calculator.random function to return a random integer between 1-10(including 10). Write a test for this to test that it's always returning a number between 1-10.