CODEWITHSUNDEEP
javascriptnode.jsjestjs
I'll-Be-Back
I'll-Be-Back

Reputation: 10828

How do I test (jest) to expect return?

Using Jest how do I test for return

For example using Lambda:

exports.handler = async (event, context, callback) => {
  try {
    const orders = await getOrders();

    if (!orders) {
      console.log("There is no Orders");
      return; //<< How do test this?
    }

    // Something else
  } catch (err) {
    throw new;
  }
};

I am able to test the console log but I also like to test to expect return as well

Currently I am using this in the test:

  it("should terminate if there is no order", async () => {
    console.log = jest.fn();

    let order = await func.handler();
     expect(console.log.mock.calls[0][0]).toBe('There is no Orders');
  });

Upvotes: 6

Views: 13171

Answers (3)

Michael Stets
Michael Stets

Reputation: 98

Necroposting here, but jest now has toReturn and toReturnWith, without and with arguments assessing, accordingly. And also there are toHaveReturned and toHaveReturnedWith to fit new language.

You can use it on spyOn'ed variant of your handler:

it("should terminate if there is no order", async () => {
  jest.spyOn(func, "handler")
  console.log = jest.fn();

  let order = await func.handler();
  expect(func.handler).toHaveReturned();
});

Upvotes: 1

Derek 朕會功夫
Derek 朕會功夫

Reputation: 94319

Simply expect the value to be undefined:

expect(order).toBeUndefined();

Upvotes: 0

artur bień
artur bień

Reputation: 121

Function with no return will return 'undefined' so you can test for that using not.toBeUndefined();

Upvotes: 8

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