How to test SSM getParameter method in jasmine? - node.js

Question

How do I test something like this?
const ssmParameterData = await ssm.getParameter(params, async (error, data) => {
if (error) throw error;
return data;
}).promise();
I have tried just mocking the method
spyOn(ssm, 'getParameter').and.returnValue(ssmParams);
and I get error like
TypeError: Cannot read property 'promise' of undefined

Answer 1

Here is the unit test solution:
index.js:
const AWS = require('aws-sdk');
const ssm = new AWS.SSM();
async function main(params) {
const ssmParameterData = await ssm
.getParameter(params, (error, data) => {
if (error) throw error;
return data;
})
.promise();
return ssmParameterData;
}
module.exports = { ssm, main };
index.test.js:
const { ssm, main } = require('./');
describe('60138152', () => {
it('should pass', async () => {
const data = 'fake data';
const getParameterRequestStub = { promise: jasmine.createSpy('promise') };
const getParameterStub = spyOn(ssm, 'getParameter').and.callFake((params, callback) => {
callback(null, data);
getParameterRequestStub.promise.and.resolveTo(data);
return getParameterRequestStub;
});
await expectAsync(main('test params')).toBeResolvedTo('fake data');
expect(getParameterStub).toHaveBeenCalledWith('test params', jasmine.any(Function));
expect(getParameterRequestStub.promise).toHaveBeenCalledTimes(1);
});
it('should throw error', async () => {
const mError = new Error('network');
const getParameterRequestStub = { promise: jasmine.createSpy('promise') };
const getParameterStub = spyOn(ssm, 'getParameter').and.callFake((params, callback) => {
callback(mError);
getParameterRequestStub.promise.and.rejectWith(mError);
return getParameterRequestStub;
});
await expectAsync(main('test params')).toBeRejectedWithError('network');
expect(getParameterStub).toHaveBeenCalledWith('test params', jasmine.any(Function));
});
});
unit test results with 100% coverage:
Executing 2 defined specs...
Running in random order... (seed: 87758)
Test Suites & Specs:
(node:93291) ExperimentalWarning: The fs.promises API is experimental
1. 60138152
✔ should pass (10ms)
✔ should throw error (1ms)
>> Done!
Summary:
👊 Passed
Suites: 1 of 1
Specs: 2 of 2
Expects: 5 (0 failures)
Finished in 0.034 seconds
----------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
----------|---------|----------|---------|---------|-------------------
All files | 100 | 100 | 100 | 100 |
index.js | 100 | 100 | 100 | 100 |
----------|---------|----------|---------|---------|-------------------
source code: https://github.com/mrdulin/jasmine-examples/tree/master/src/stackoverflow/60138152