0

I am trying to set up jest and run a simple test (sum from jestjs.io).

sum.ts file:

function sum(a: any, b: any):any {
  return a + b;
}
module.exports = sum;

sum.test.ts file:

const sum = require('./sum');

test('adds 1 + 2 to equal 3', () => {
  expect(sum(1, 2)).toBe(3);
});

In the console I am getting:

yarn test
yarn run v1.22.17
warning ../../../package.json: No license field
$ jest
 FAIL  src/sum.test.ts
  ● Test suite failed to run

    src/sum.test.ts:1:7 - error TS2451: Cannot redeclare block-scoped variable 'sum'.

    1 const sum = require('./sum');
            ~~~

      src/sum.ts:1:10
        1 function sum(a: any, b: any) {
                   ~~~
        'sum' was also declared here.

Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        0.87 s
Ran all test suites.
error Command failed with exit code 1.

How to resolve this?

If change import in the file 'sum.test.ts' like this,

import { sum } from './sum'

test('adds 1 + 2 to equal 3', () => {
  expect(sum(1, 2)).toBe(3);
});

Console:

yarn test
yarn run v1.22.17
warning ../../../package.json: No license field
$ jest
 FAIL  src/sum.test.ts
  ● Test suite failed to run

    src/sum.test.ts:1:21 - error TS2306: File '/Users/pasmo/Code/sandbox/.../src/sum.ts' is not a module.

    1 import { sum } from './sum'
                          ~~~~~~~

Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        0.812 s
Ran all test suites.
error Command failed with exit code 1.

................

track_p54skate
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1 Answers1

0

the answer is:

file sum.ts

export function sum(a: number, b: number) {
  return a + b;
}
track_p54skate
  • 81
  • 1
  • 6