Mock Xrm.WebApi.retrieveRecord(...).then in Jasmine Unit test without using any other node module

In the describe/beforeEach/it add below :

For Successful call:

 Xrm: {

  WebApi: {

        retrieveRecord: () => {

            //Add the result Object Properties to this object below

            var retrieveRecordResult = {

            };

            return Promise.resolve(retrieveRecordResult);

        }

        retrieveMultipleRecords: () => {

            //Add the result array Properties to this object below

            var retrieveMultipleRecordsResults = {

                entities: [{ fieldName: fieldValue, anotherFiedName: anotherFieldValue }]

            };

            return Promise.resolve(retrieveMultipleRecordsResults);

        }

    }

}

  window['Xrm']=Xrm;

For Error in the call:

Xrm: {

    WebApi: {

        retrieveRecord: () => {

            //Add the result Object Properties to this object below

            var retrieveRecordError = {

                message: 'Error in retrieve Multiple'

            };

            return Promise.reject(retrieveRecordError);

        }

        retrieveMultipleRecords: () => {

            //Add the result array Properties to this object below

            var retrieveMultipleRecordsError = {

                message: 'Error in retrieve Multiple'

            };

            return Promise.reject(retrieveMultipleRecordsError);

        }

    }

}

  window['Xrm']=Xrm;