Newman using external parameter files

In

Required software

  • Postman (the GUI makes everything simpler)
  • NodeJS (recommended: latest LTS version)
  • Newman package, plus custom reporters (e.g. htmlextra) 
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    npm install -g newman
    # install some extra reporter if you like
    npm install -g newman-reporter-htmlextra

The Postman collection script

You will work with Postman as usual. The Postman collection runner is behind the Workspaces which require a Postman account. However, you may run it on Newman without any need for account.

Format

Item Format
Environment variables "{{MESSAGE}}"
Script variable data.message

Parameters on request data

  • You can have parameteres on Body -> Raw.

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    {
        "text": "{{MESSAGE}}"
    }

  • We are getting that parameter from an environment variable. We configure that on a request script, in order to redirect it to the external data file.

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    pm.environment.set("MESSAGE", data.message);

Parameters on test scripts

  • We can pass the parameters directly to this code excerpts. Postman provides snippets to make this task faster. 
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    pm.test("Status code is 200", function () {
        pm.response.to.have.status(200);
    });
    pm.test("Check if the text was properly sent", function () {
        var jsonData = pm.response.json();
        pm.expect(jsonData.contents.text).to.eql(data.message);
    });
    pm.test("Check if translation was correct", function () {
        var jsonData = pm.response.json();
        pm.expect(jsonData.contents.translated).to.eql(data.expected_translation);
    });

Full exported code

  • Go to the collection menu, and select export. You will get a json file.

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    {
        "info": {
            "_postman_id": "2d07d2fd-5350-4959-8f41-a1d091826933",
            "name": "Fun translations",
            "description": "A few funny translations, like talking as Yoda",
            "schema": "https://schema.getpostman.com/json/collection/v2.1.0/collection.json"
        },
        "item": [
            {
                "name": "Yoda",
                "event": [
                    {
                        "listen": "test",
                        "script": {
                            "exec": [
                                "pm.test(\"Status code is 200\", function () {\r",
                                "    pm.response.to.have.status(200);\r",
                                "});\r",
                                "pm.test(\"Check if the text was properly sent\", function () {\r",
                                "    var jsonData = pm.response.json();\r",
                                "    pm.expect(jsonData.contents.text).to.eql(data.message);\r",
                                "});\r",
                                "pm.test(\"Check if translation was correct\", function () {\r",
                                "    var jsonData = pm.response.json();\r",
                                "    pm.expect(jsonData.contents.translated).to.eql(data.expected_translation);\r",
                                "});"
                            ],
                            "type": "text/javascript"
                        }
                    },
                    {
                        "listen": "prerequest",
                        "script": {
                            "exec": [
                                "pm.environment.set(\"MESSAGE\", data.message);"
                            ],
                            "type": "text/javascript"
                        }
                    }
                ],
                "request": {
                    "method": "POST",
                    "header": [],
                    "body": {
                        "mode": "raw",
                        "raw": "{\r\n    \"text\": \"{{MESSAGE}}\"\r\n}\r\n",
                        "options": {
                            "raw": {
                                "language": "json"
                            }
                        }
                    },
                    "url": {
                        "raw": "https://api.funtranslations.com/translate/yoda",
                        "protocol": "https",
                        "host": [
                            "api",
                            "funtranslations",
                            "com"
                        ],
                        "path": [
                            "translate",
                            "yoda"
                        ]
                    },
                    "description": "Post query to talk like Yoda.\n- It needs to fill the body of the request"
                },
                "response": []
            }
        ]
    }

The external file

CSV

Format

  • The first line will contain the name of the fields.
  • The following lines wil contain the values of those fields for each iteration.

Full Code

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message, expected_translation
"This is a message", "A message,  this is"
"This is a dummy", "A dummy,  this is"

Json

Format

  • It is represented as a list of Json objects.
  • Each object must have its attributes defined as key-value pairs.

Full Code

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[
    {
        "message": "This is a message",
        "expected_translation": "A message,  this is"
    },
    {
        "message": "This is a dummy",
        "expected_translation": "A dummy,  this is"
    }
]

Run it

You can run the Newman command from the command line.

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newman run FunTranslations.postman_collection.json -d data-translate.csv -r cli,htmlextra
newman run FunTranslations.postman_collection.json -d data-translate.json -r cli,htmlextra