How can i make a function always return the same result on my test

Question

i have a function named "exchange" that depends of another named "getQuote", that returns a value from an api. How can i make "getQuote" always return a specific value to test "exchange"

getQuote function:

async function getQuote(from_symbol: string, to_symbol: string): Promise<any>{
    const options = {
        method: 'GET',
        url: 'https://alpha-vantage.p.rapidapi.com/query',
        params: {
            from_symbol: from_symbol,
            function: 'FX_INTRADAY',
            interval: '5min',
            to_symbol: to_symbol,
            outputsize: 'compact',
            datatype: 'json'
        },
        headers: {
            'X-RapidAPI-Key': API_KEY,
            'X-RapidAPI-Host': 'alpha-vantage.p.rapidapi.com'
        }
    };

    try{
        let response = await axios.request(options);
        let QuoteData = await response.data;
        let current_time = (QuoteData["Meta Data"]["4. Last Refreshed"]);
        let quote_data = (QuoteData["Time Series FX (5min)"][current_time]);
        let quote_value: number = parseFloat(quote_data["1. open"]);
        return quote_value
    }catch(err){
        console.log(err);
    }
};

exchange function:

    async exchange(cash: number, from_coin: string, to_coin: string): Promise<void>{
        if(this.cash[from_coin] < cash) return;

        this.removeCash(cash,from_coin);

        let quote: number = await getQuote(from_coin, to_coin);
        let converted_cash = cash * quote;

        this.deposite(converted_cash, to_coin);
    }

my unitary test:

describe("testing user methods", ()=>{
    const user = new User({cash: {"BRL": 100, "USD": 0}});
    it("exchange should work", ()=>{
        let value = 100;
        let from_coin = "BRL";
        let to_coin = "USD";

        user.exchange(value,from_coin,to_coin);
        expect(user.cash["USD"]).toBe(19.2);
    })
});

i tried to mock "axios" but it always returns undefined, i don't have idea what to do;

score 0 · Answer 1 · answered Feb 15 '23 at 13:46

In this unit test, your concern is with testing the exchange function. So you should just mock getQuote itself to return the values you want and forget about Axios here.

In a separate test for getQuote, you can deal with mocking axios. How do I test axios in Jest?

How can i make a function always return the same result on my test

1 Answers1