The it() and test() functions in Jest are both used to define tests. However, there is a subtle difference between the two.

The it() function is an alias for the test() function. This means that you can use either function to define a test. However, the it() function is often used to define more readable tests.

For example, the following two code snippets are equivalent:

test("should return the sum of two numbers", () => {
  const result = myFunction(10, 20);
  expect(result).toBe(30);
});

it("should return the sum of two numbers", () => {
  const result = myFunction(10, 20);
  expect(result).toBe(30);
});

The first code snippet uses the test() function, while the second code snippet uses the it() function. The second code snippet is more readable because it uses a sentence-like structure.

Ultimately, the choice of whether to use the it() or test() function is up to you. However, the it() function is often a good choice for creating more readable tests.