# Testing with Insomnia for IES
source: https://developer.mastercard.com/account-to-account-commerce-for-dsp/tutorial/insomnia-ies/index.md

### Overview {#overview}

Participants are often expected to validate the complete agreement lifecycle or payment journey when supporting Mastercard® Account‑to‑Account Commerce. This requires true end‑to‑end testing, where each interaction behaves exactly as it would in a real-world ecosystem.   

This guide empowers Participants to step into the shoes of the opposite entity, allowing them to accurately simulate counterpart behavior and drive their test cases to successful completion. By doing so, teams can confidently validate integrations without waiting on external dependencies.   

The Insomnia pack serves as a practical companion throughout this process, offering a clear view of sample request and response payloads and helping Participants understand how each API interaction should look and behave.   

From downloading Insomnia to executing calls and validating outcomes, this guide walks through the journey step by step, ensuring Participants can set up their environment, run tests seamlessly, and verify results with confidence.

### What You Will Learn {#what-you-will-learn}

* How to install Insomnia
* Steps to install the Mastercard plugin for Insomnia
* The process for importing test packs
* Configuring environment variables and certificates
* Executing Mastercard API calls using Insomnia

### Pre-Requisites {#pre-requisites}

Mastercard provides DSPs with Insomnia test packs containing scripts to simulate responses received from a CSP. Before testing Account to Account Commerce APIs with Insomnia, ensure the following prerequisites are met:   

* Create a project for the Mastercard Account to Account Commerce API. Refer to the 'Creating a Sandbox Project' section for details.
* Download and install the [Insomnia tool](https://insomnia.rest/).
* Install the Mastercard Insomnia Plugin.
* Download the Insomnia test pack containing test cases and other supporting files in [DSP PACK FOR IEXS.](https://static.developer.mastercard.com/content/account-to-account-commerce-for-dsp/uploads/DSP_PACK_FOR_IEXS.zip)
[](https://static.developer.mastercard.com/content/account-to-account-commerce-for-dsp/uploads/DSP_PACK_FOR_IEXS.zip)
* [Review the test cases](https://static.developer.mastercard.com/content/account-to-account-commerce-for-dsp/uploads/DSP_PACK_FOR_IEXS.zip)[IES DSP Test Cases V1.0](/uploads/IES DSP Test Cases V1.0.xlsx).

**Note**: DSP Pack for IEXS zip files contains the following items:

|                     Item                     |                Type                |
|----------------------------------------------|------------------------------------|
| A2A-MTF-TEST-CLIENT.pfx                      | Client certificate                 |
| decryption-private-keymtf.key                | MTF key file                       |
| DSP_Customer-Accrediation-Pack-for-IEXS.yaml | yaml file                          |
| encryptioncertmtf.pem                        | Security Certificate               |
| signcertificate.key                          | Signature certificate              |
| signverificationcertificate.pem              | Signature Verification Certificate |

![iexsfolder](https://static.developer.mastercard.com/content/account-to-account-commerce-for-dsp/uploads/insomnia-slides/iexsfolder.png)

### Self-Test Environment Overview {#self-test-environment-overview}

The test pack covers the following use cases:   

#### Get List of CSPs {#get-list-of-csps}

#### Send Alias Resolution Request {#send-alias-resolution-request}

* Send Alias Resolution for Alias Type "EMAL"
* Send Alias Resolution for Alias Type "PHON"

#### Receive Alias Resolution Update for below scenarios: {#receive-alias-resolution-update-for-below-scenarios}

* Alias Resolution Successful
  * Receive Bank Account Details Associated with Alias
  * Receive Wallet Account Details Associated with Alias
* Alias Resolution Rejected (MULT)
* Alias Resolution Rejected (NTFD)
* Alias Resolution Rejected (ACCD)
* Alias Resolution Rejected (LCNF)
* Alias Resolution Rejected (OTHR)