As a Node module, assert can be imported at the top of your files with

const assert = require('assert');

The functions in the assert library compare values and throw errors as needed using one function call. The small, human-readable format of the functions will help you make a more expressive test suite.

assert.ok(6 - 1 === 5);

In this case 6 - 1 === 5 evaluates to true, so no error is thrown.

If an argument passed to assert.ok() evaluates to false, an AssertionError is thrown. The error communicates to Mocha that a test has failed, and Mocha logs the error message to the console.



At the top of index_test.js, import assert with the require function.


Within the provided it block, enter the following expression:

assert.ok(result === 91);

Run the test suite.


The argument passed to assert.ok() throws an error! You should see some descriptive feedback in the terminal.

Make the expression evaluate to true by replacing 91 with expected.


Run the suite again. Your test should pass now!

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