# Comparisons
source: https://developer.mastercard.com/carbon-calculator/documentation/testing/testcase/test_case_engagement_comparisons/index.md

**Comparisons** provide a comparison of CO2 emissions in tonnes with everyday life examples.

## Pre-requisites {#pre-requisites}

Refer to the [Comparisons](https://developer.mastercard.com/carbon-calculator/documentation/use-cases/engagement-services/comparisons/index.md) use case.


API Reference: `GET /comparisons`

<br />

## Test Cases {#test-cases}

### Test Case: Success-Comparisons {#test-case-success-comparisons}

##### Request {#request}

    {{host}}/comparisons

##### Response {#response}

```json
{
    "content": "Dolore proident reprehenderit mollit aute tempor anim fugiat voluptate laboris. Nulla cupidatat ex eu aute id tempor pariatur sint ad laboris exercitation qui. Est consectetur excepteur sint nisi velit proident anim nisi ipsum exercitation eiusmod.\nQuis ex anim magna do amet cupidatat ex labore exercitation minim duis consequat occaecat. Officia commodo tempor eiusmod velit id eu pariatur laboris aliqua proident et dolore officia. Tempor laborum ipsum tempor consectetur excepteur ea non ut cillum aliqua. Exercitation mollit proident voluptate aliquip deserunt nisi sit proident minim irure tempor sit velit excepteur. Velit incididunt in dolore minim eiusmod incididunt.",
    "description": "Emissions related to production",
    "id": "9",
    "language": "en",
    "mainCategory": "shopping",
    "source": "ADEME, France, \"Modélisation et évaluation du poids carbone de produits de consommation et biens d'équipement\"",
    "sourceLink": "https://librairie.ademe.fr/consommer-autrement/1190-modelisation-et-evaluation-du-poids-carbone-de-produits-de-consommation-et-biens-d-equipement.html",
    "spendingAreaId": "30",
    "tonne": "1"
}
```

### Test Case: Fail-Invalid request parameter {#test-case-fail-invalid-request-parameter}

##### Request {#request-1}

    {{host}}/comparisons?language=abc

##### Response {#response-1}

```json
{
    "Errors": {
        "Error": [
            {
                "Source": "Carbon-Calculator",
                "ReasonCode": "INVALID_REQUEST_PARAMETER",
                "Description": "One of the request parameters is invalid, try again with correct request.",
                "Recoverable": false,
                "Details": "Language codes must follow ISO 639-1 format (example: 'en')"
            }
        ]
    }
}
```

### Test Case: Fail-Invalid request parameter-tonne {#test-case-fail-invalid-request-parameter-tonne}

##### Request {#request-2}

    {{host}}/comparisons?tonne=7

##### Response {#response-2}

```json
{
  "Errors": {
    "Error": [
      {
        "Source": "Carbon-Calculator",
        "ReasonCode": "INVALID_REQUEST_PARAMETER",
        "Description": "One of the request parameters is invalid, try again with correct request.",
        "Recoverable": false,
        "Details": "Tonne must be one of the following values: 1, 5, 10"
      }
    ]
  }
}
```

### Test Case: Comparison not found {#test-case-comparison-not-found}

##### Request {#request-3}

    {{host}}/comparisons?main_category=electronics

##### Response {#response-3}

```json
{}
```