mock nodemailer.createTransport.sendMail with jest












0














I have some code which uses the nodemailer module.



In the router (router.js), I have



const transporter = nodeMailer.createTransport(emailArgs);


Then inside the route (/login) I have:



...
return transporter.sendMail(mailOptions);


I'm trying to test this route using the jest testing framework. I'm having some trouble mocking out the call to sendMail. I read this nice blogpost about how to use jest mocking, but I'm getting this error:




TypeError: Cannot read property 'sendMail' of undefined




And indeed when I check the value of transporter it's undefined.



Here is my testing code (which doesn't work):



import request from "supertest";
import router from "./router";

jest.mock("nodemailer");

describe("", () => {
...

test("", async () => {
// 1 - 200 status code; 2 - check email was sent
expect.assertions(2);

const response = await request(router)
.post("/login")
// global variable
.send({ "email": email })
.set("Accept", "application/json")
.expect("Content-Type", /json/);

// should complete successfully
expect(response.status).toBe(200);
// TODO not sure how to express the expect statement here
});
});


So my question is how do I mock out a method of an instance of a class which is returned by a module?










share|improve this question





























    0














    I have some code which uses the nodemailer module.



    In the router (router.js), I have



    const transporter = nodeMailer.createTransport(emailArgs);


    Then inside the route (/login) I have:



    ...
    return transporter.sendMail(mailOptions);


    I'm trying to test this route using the jest testing framework. I'm having some trouble mocking out the call to sendMail. I read this nice blogpost about how to use jest mocking, but I'm getting this error:




    TypeError: Cannot read property 'sendMail' of undefined




    And indeed when I check the value of transporter it's undefined.



    Here is my testing code (which doesn't work):



    import request from "supertest";
    import router from "./router";

    jest.mock("nodemailer");

    describe("", () => {
    ...

    test("", async () => {
    // 1 - 200 status code; 2 - check email was sent
    expect.assertions(2);

    const response = await request(router)
    .post("/login")
    // global variable
    .send({ "email": email })
    .set("Accept", "application/json")
    .expect("Content-Type", /json/);

    // should complete successfully
    expect(response.status).toBe(200);
    // TODO not sure how to express the expect statement here
    });
    });


    So my question is how do I mock out a method of an instance of a class which is returned by a module?










    share|improve this question



























      0












      0








      0







      I have some code which uses the nodemailer module.



      In the router (router.js), I have



      const transporter = nodeMailer.createTransport(emailArgs);


      Then inside the route (/login) I have:



      ...
      return transporter.sendMail(mailOptions);


      I'm trying to test this route using the jest testing framework. I'm having some trouble mocking out the call to sendMail. I read this nice blogpost about how to use jest mocking, but I'm getting this error:




      TypeError: Cannot read property 'sendMail' of undefined




      And indeed when I check the value of transporter it's undefined.



      Here is my testing code (which doesn't work):



      import request from "supertest";
      import router from "./router";

      jest.mock("nodemailer");

      describe("", () => {
      ...

      test("", async () => {
      // 1 - 200 status code; 2 - check email was sent
      expect.assertions(2);

      const response = await request(router)
      .post("/login")
      // global variable
      .send({ "email": email })
      .set("Accept", "application/json")
      .expect("Content-Type", /json/);

      // should complete successfully
      expect(response.status).toBe(200);
      // TODO not sure how to express the expect statement here
      });
      });


      So my question is how do I mock out a method of an instance of a class which is returned by a module?










      share|improve this question















      I have some code which uses the nodemailer module.



      In the router (router.js), I have



      const transporter = nodeMailer.createTransport(emailArgs);


      Then inside the route (/login) I have:



      ...
      return transporter.sendMail(mailOptions);


      I'm trying to test this route using the jest testing framework. I'm having some trouble mocking out the call to sendMail. I read this nice blogpost about how to use jest mocking, but I'm getting this error:




      TypeError: Cannot read property 'sendMail' of undefined




      And indeed when I check the value of transporter it's undefined.



      Here is my testing code (which doesn't work):



      import request from "supertest";
      import router from "./router";

      jest.mock("nodemailer");

      describe("", () => {
      ...

      test("", async () => {
      // 1 - 200 status code; 2 - check email was sent
      expect.assertions(2);

      const response = await request(router)
      .post("/login")
      // global variable
      .send({ "email": email })
      .set("Accept", "application/json")
      .expect("Content-Type", /json/);

      // should complete successfully
      expect(response.status).toBe(200);
      // TODO not sure how to express the expect statement here
      });
      });


      So my question is how do I mock out a method of an instance of a class which is returned by a module?







      node.js unit-testing mocking jestjs nodemailer






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Nov 22 '18 at 10:23









      skyboyer

      3,40611128




      3,40611128










      asked Nov 21 '18 at 21:14









      BlackSheepBlackSheep

      1,43973258




      1,43973258
























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