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Scripts

Postdata lets you add dynamic behavior to REST requests. This allows you to write test suites and build requests that can contain dynamic parameters. You can add JavaScript code that executes at two events in the flow:
  • Tests are executed after a response is received from the server
  • You can add multiple tests to a request
  • You can add tests to both requests saved and not saved in a collection
Postdata will then execute the scripts after the response is received.

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Post-request tests

As you introduce new code, tests ensure that your API is working as intended. The higher your test coverage, the more flexible and bug-resistant your code will be. You’ll be spending less time wondering why deleting a picture of a coconut breaks your code.

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Writing post-request tests

Postdata ships a powerful API called pw which can handle post-request scripts as well as tests. Here we’ll use pw to run tests on the response received from APIs.

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Examples

Let us look at some examples of how you can use Postdata to write tests.

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Test response status code

Let us write a test to check whether the response to our request has a status code of 200. Which means that there are no errors in the response body. We’ll use the below URL with the GET method. 
https://www.httpbin.org/status/200
In this case, we’ll need to write two expect statements one for checking the status and another for checking the response body. However, we can wrap expect statements with the test method from the pw API to group related statements. There are two ways to test the status code:
ConditionCode
Check if response code is 200pw.expect(pw.response.status).toBe(200)
In-built matcher functionpw.expect(pw.response.status).toBeLevel2xx()
pw.test("Response is ok", () => {
  pw.expect(pw.response.status).toBe(200);
});
The tests will have passed once you click on the “Send” button.

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Assert response payload

In this example, we test whether a user id points to a particular user. Let us use the following GET API endpoint 
https://reqres.in/api/users/10
We will use .toBe() to assert specific values and .toBeType() to assert specific data types as shown in the code snippet below: 
pw.test("Check first name", () => {
  const user = pw.response.body.data;
  pw.expect(user.first_name).toBe("Byron");
  pw.expect(user.first_name).toBeType("string");
});
Running the test will produce the result as shown below: