We don't write tests to pass, we write them to fail. Because every failed test is one unexpected behavior we caught, and one bug less for our users to experience.

Let's run our greet.ts file now and see what happens.

npx tsx greet.ts

Oh! Suddenly, the process exits with an error:

Error: Expected message to equal to "Hello, John!" but got "Howdy, John!"

This is our test throwing an error to let us know that something doesn't seem right. If you take a closer look at the error message, you can spot that the greeting string returned from the greet function is different from what we expected. That's precisely why we need tests—to tell us when and what goes wrong.

👨‍💼 In this exercise, you have to fix this problem and make the test pass again (have the npx tsx greet.ts exit without errors).