Mocking a class in typescript with jest - class

Question

I am trying to unit test (with Jest) my handler module that makes use of a summary class.
My original summary class looks like:
import DynamoDBClient from './ddbClient/DynamoDBClient'
import { DynamoDB } from 'aws-sdk'
import { iSummaryReader, iObsSummariesAttributes } from './Summary.d'
import { JSONAPIResource } from '../JSONAPIResponse'
export default class Summary {
reader: iSummaryReader
constructor(reader: iSummaryReader) {
this.reader = reader
}
getSummary = async (keyName: string, keyValue: string): Promise<JSONAPIResource<iObsSummariesAttributes>> => {
return new Promise<JSONAPIResource<iObsSummariesAttributes>>((resolve, reject) => {
const gettingItem = this.reader.getItem(keyName, keyValue)
console.log(gettingItem)
gettingItem.then((resp) => {
resolve(resp)
}).catch((err: Error) => {
reject(err.message)
})
})
}
}
In my handler module I import with import Summary from './lib/Summary'
(Note: same line is used in handler.test.ts
Inside the handler function
try {
const dynamodbObj: iSummaryReader = new DynamoDBClient(documentClient, someTable)
const summary = new Summary(dynamodbObj)
const data: JSONAPIResource<iObsSummariesAttributes> = await summary.getSummary('id', someID)
}
My results depend on my approach if try an automatic mock
jest.mock('./lib/Summary', () =>
{
return {
getSummary: jest.fn()
}
})
I get the error
TypeError: Summary_1.default is not a constructor
If I create a manual mock under lib/__mocks__/Summary.ts with jest.mock('./lib/Summary') it does work until I get the point
expect(Summary).toHaveBeenCalledTimes(1)
Where it complains about me not being able to do this on summary. I also am unable to access my method to test that they are being called this way.
Note: My hanlder is for a lambda function so I am unable to inject the class that way where I have successfully tested that I can mock an injected class.
EDIT
The tsconfig.json is:
{
"compilerOptions": {
"rootDir": "./src",
"outDir": "./build",
"declaration": false,
"target": "es2015",
"moduleResolution": "node",
"module": "commonjs",
"noImplicitReturns": true,
"noImplicitThis": true,
"strictNullChecks": true,
"alwaysStrict": true,
"lib": [
"dom",
"es2015.promise",
"es2017.object",
"es2016"
],
},
"include": [
"src/**/*.ts"
],
}

Answer 1

I do not know why this was failing, but I the following steps seem to work to fix it.
Change the class export from default
From
`export default class Summary {`
to
`class summary`
+ export = summary at the end
Use import = require to import it.
import Summary = require('./lib/Summary')
Those two changes allowed it to find the jest.mock.