To test an if condition and return statement inside a function using Jest, you can do the following:

1. Write a test function that calls the function you want to test and pass in the necessary arguments.
2. Use the expect function to assert that the return value of the function is what you expect it to be. For example:

test('function should return correct value', () => {
const result = myFunction(arg1, arg2);
expect(result).toBe(expectedValue);
});

3. Run the test using the jest command.

Here’s an example of a function and a test for it:

function myFunction(arg1, arg2) {
if (arg1 > arg2) {
return 'arg1 is greater';
} else {
return 'arg2 is greater';
}
}

test('function should return correct value', () => {
const result = myFunction(2, 3);
expect(result).toBe('arg2 is greater');
});

In this example, the test function calls myFunction with the arguments 2 and 3, and then uses the expect function to assert that the return value is 'arg2 is greater'. When you run the test using the jest command, it will pass if the function returns the expected value.