What Is the Difference Between ‘it’ and ‘test’ in Jest?

What is the difference between ‘it’ and ‘test’ in Jest?

When writing tests using Jest, you may have come across the terms ‘it’ and ‘test’ and wondered what the difference between them is. In this article, we will explore the distinctions between these two keywords in Jest and how they can be used in your test suite.

The ‘it’ Function

The ‘it’ function is used to define an individual test case in Jest. It is a shorthand for the ‘test’ function and provides a descriptive name for the specific test scenario you are writing. The ‘it’ function takes two arguments: a string description of the test and a callback function that contains the test logic.

Here’s an example of how the ‘it’ function can be used:

it('should return the sum of two numbers', () => {
  const result = sum(2, 3);
  expect(result).toBe(5);
});

In the above example, we define a test case using the ‘it’ function. The description provided (‘should return the sum of two numbers’) gives a clear indication of what the test is trying to achieve. Inside the callback function, we perform the necessary calculations and use the ‘expect’ function to make assertions about the expected outcome.

The ‘test’ Function

The ‘test’ function is an alternative to the ‘it’ function in Jest. It serves the same purpose of defining a test case but allows for a more descriptive name. While ‘it’ is commonly used for shorter test descriptions, ‘test’ can be used for longer and more detailed descriptions.

Here’s an example of how the ‘test’ function can be used:

test('should return the sum of two numbers', () => {
  const result = sum(2, 3);
  expect(result).toBe(5);
});

In this example, we define the same test case as before, but this time using the ‘test’ function. The test description is more explicit, providing additional context for the test case.

Choosing Between ‘it’ and ‘test’

When deciding whether to use ‘it’ or ‘test’, it ultimately comes down to personal preference and the level of detail you want to include in your test descriptions. Both keywords serve the same purpose and can be used interchangeably without affecting the functionality of your tests.

It’s worth noting that the ‘it’ and ‘test’ functions can be nested within each other to create a hierarchical structure for your test suite. This can be useful when organizing and categorizing your tests.

Conclusion

In Jest, the ‘it’ and ‘test’ functions are used to define individual test cases. While ‘it’ provides a concise way to describe a test, ‘test’ allows for more detailed descriptions. Both keywords can be used interchangeably, and the choice between them depends on personal preference and the level of detail you want to include in your test descriptions.

Now that you understand the difference between ‘it’ and ‘test’ in Jest, you can choose the one that best suits your testing needs and write more descriptive and organized test cases.