I have a mock version of the aws-sdk, which works fine in my tests:
jest.mock("aws-sdk", () => {
return {
Credentials: jest.fn().mockImplementation(() => ({})),
Config: jest.fn().mockImplementation(() => ({})),
config: {
update: jest.fn(),
},
S3: jest.fn().mockImplementation(() => ({
getSignedUrlPromise: awsGetSignedUrlMock,
})),
SQS: jest.fn().mockImplementation(() => ({})),
};
});
However many of my tests use the mock AWS SDK, and I would like to not repeat the mock code unnecessarily. If I move the function into a separate file and import it, however, this will fail:
In my testSupport.ts file:
export const mockAwsSdk = () => {
return {
Credentials: jest.fn().mockImplementation(() => ({})),
Config: jest.fn().mockImplementation(() => ({})),
config: {
update: jest.fn(),
},
S3: jest.fn().mockImplementation(() => ({
getSignedUrlPromise: awsGetSignedUrlMock,
})),
SQS: jest.fn().mockImplementation(() => ({})),
};
};
In the test file:
jest.mock("aws-sdk", mockAwsSdk);
This fails with:
ReferenceError: Cannot access 'testSupport_1' before initialization
I have tried various solutions, including making a parent function that takes the jest instance, but I still haven't been able to get this to work.
How can I share jest mocks between multiple tests?
I have a mock version of the aws-sdk, which works fine in my tests:
jest.mock("aws-sdk", () => {
return {
Credentials: jest.fn().mockImplementation(() => ({})),
Config: jest.fn().mockImplementation(() => ({})),
config: {
update: jest.fn(),
},
S3: jest.fn().mockImplementation(() => ({
getSignedUrlPromise: awsGetSignedUrlMock,
})),
SQS: jest.fn().mockImplementation(() => ({})),
};
});
However many of my tests use the mock AWS SDK, and I would like to not repeat the mock code unnecessarily. If I move the function into a separate file and import it, however, this will fail:
In my testSupport.ts file:
export const mockAwsSdk = () => {
return {
Credentials: jest.fn().mockImplementation(() => ({})),
Config: jest.fn().mockImplementation(() => ({})),
config: {
update: jest.fn(),
},
S3: jest.fn().mockImplementation(() => ({
getSignedUrlPromise: awsGetSignedUrlMock,
})),
SQS: jest.fn().mockImplementation(() => ({})),
};
};
In the test file:
jest.mock("aws-sdk", mockAwsSdk);
This fails with:
ReferenceError: Cannot access 'testSupport_1' before initialization
I have tried various solutions, including making a parent function that takes the jest instance, but I still haven't been able to get this to work.
How can I share jest mocks between multiple tests?
Share Improve this question asked Jul 2, 2020 at 11:43 mikemaccanamikemaccana 124k110 gold badges430 silver badges533 bronze badges2 Answers
Reset to default 4Jest has a moduleNameMapper config property which can be used to specify a string or regular expression to match your import and replace it with a mock file
Alternatively, you can add mocks without specifying it in the moduleNameMapper by placing your mock file in a folder named __mocks__ which should be in the same directory as the file you need to mock
In case it is in node_modules, the __mocks__ folder should be in your parent directory.
I had the same issue and solved my problem using setupFiles.
Create a jest.config.js file:
const config = {
setupFiles: ['./src/setupFiles.js']
}
export default config
Then you can write your shared mocks in setupFiles.js
import { Logger } from 'from-some-package'
jest.spyOn(Logger, 'init').mockImplementation(() => jest.fn())
jest.spyOn(Logger, 'info').mockImplementation(() => jest.fn())
jest.spyOn(Logger, 'debug').mockImplementation(() => jest.fn())
jest.spyOn(Logger, 'error').mockImplementation(() => jest.fn())
jest.mock('third-party-package');
global.fetch = jest.fn()