Using CPF generator in Postman

Question

I am performing several registration tests via Postman and I would like to know if there is any way to automatically generate a CPF in the POST body that I am sending.

Who knows via Faker?

Answer 1

For any kind of data you can set the variables in the Pre-request Script, whether it is a random value for CPF or for something else.

Use pm.globals to define a global variable, example:

pm.globals.set("foo", "bar");

Use pm.collectionVariables to set a variable for collection, example:

pm.collectionVariables.set("foo", "bar");

Use pm.environmentto set a variable for the Environment (in the currently selected environment, check in the menu the option Environment):

pm.environment.set("foo", "bar");

If you have view but not edit access to an Environment, your script code will only affect the current value and will not be synchronized or shared with your team.

Defining local variables

For your case set a local variable, ie no Pre-request Script, which will be a temporary value should serve very well (unless it will create a process with a dynamically triggered step by step, but depends on the case and or need), example:

pm.variables.set("foo", "bar");

It’s not necessary Faker.js, this is only a facilitator, you can write any script anyway the time you think necessary, have an example in this question of how to generate a CPF: CPF generator in Javascript

Finally do the following, in your Pre-request Script add:

pm.variables.set("cpf", gerarCPF());

function gerarCPF() {
      return ...;
}

it’s just one pseudocode to get an idea of how to implement, and then if your request is GET, do something like http://foo/bar?cpf={{cpf}}, see the result in the http://postman-echo.com/get:

If it is POST just pass the variable {{cpf}} no body, see the result in the image of http://postman-echo.com/post:

---

Integrating third party tools with pm.sendRequest

No need to use specifically Faker.js and he is not exactly integrated, in fact "integrate" is something we do using pm.sendRequest, so if you know of another library that has CPF generator, CNPJ or any other need, you can use the pm.sendRequest added to a eval (this runs in Sandbox) to inject the script:

pm.sendRequest("https://cdn.foobar/lib.js", (error, response) => {
    if (error || response.code !== 200) {
        pm.expect.fail('Could not load external library');
    }

    eval(response.text());

    pm.variables.set("cpf", gerador.CPF());
});

Some libraries use the object window to have access to lib, such as Pre-request Script wheel in a sandbox is necessary to create an object window own:

window = {};

pm.sendRequest("https://cdn.barbaz/lib.js", (error, response) => {
    if (error || response.code !== 200) {
        pm.expect.fail('Could not load external library');
    }

    eval(response.text());

    pm.variables.set("cpf", window.gerador.CPF());
});

Note that you can also use require(...) (if the used library supports), which can make it much easier.

---

Taking advantage, you can use the pm.sendRequest() to create step-by-step specific tests where you need a sequence of ordered requests to get a result, but this is a subject far beyond.

Documentation: https://learning.postman.com/docs/writing-scripts/script-references/postman-sandbox-api-reference/#sending-requests-from-scripts