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How To Use Postman For Website Testing

API Testing Blog

Using Postman for Website Testing: A Comprehensive Guide

Postman, a widely-used API testing tool, offers a powerful platform for testing various aspects of website functionality beyond just APIs. Its intuitive interface, robust features, and versatility make it a valuable asset for web developers and testers.

1. Setting Up Your Postman Environment

Before we dive into specific testing techniques, let’s set up our Postman environment.

  • Download and Install Postman: Visit the official Postman website (https://www.postman.com/) and download the appropriate version for your operating system. Install the application as usual.
  • Create a New Workspace: Workspaces help organize your requests, collections, and environments. Click on the ”+” icon in the top-left corner and select “Create Workspace.” Give your workspace a descriptive name.
  • Create a Collection: Collections group related requests together. Use the ”+” icon again and select “Create Collection.” Name your collection, e.g., “Website Testing.” This will provide a structured way to manage your tests.

2. Fundamental Website Tests with Postman

Postman allows you to test basic website functionality, even without directly interacting with APIs.

2.1. Testing Website Content:

  • GET Request: Use a GET request to fetch content from specific web pages. For example, to retrieve the homepage content of “www.example.com,” you would enter the URL in the request URL field and click “Send.”
  • Verification: In the “Response” section, you can examine the HTML content to ensure it’s displayed correctly. You can also use Postman’s built-in features to validate the content using assertions.

2.2. Form Submission:

  • POST Request: Postman facilitates submitting data through website forms. Select a POST request and provide the following:
    • URL: The action URL of your form.
    • Headers: Include necessary headers (e.g., Content-Type: application/x-www-form-urlencoded).
    • Body: Send the form data as key-value pairs in the “Body” section. For example:
    {
        "name": "John Doe",
        "email": "john.doe@example.com"
    }
  • Verification: Check the response code (usually 200 for success). Examine the response body to confirm the form was successfully processed.

2.3. Testing Redirects:

  • Send a GET request to the URL you want to test.
  • Check the Response Status Code: A 3xx status code indicates a redirect.
  • Examine the Location Header: The response header will contain a Location field indicating the URL the browser should redirect to. Use this to verify the redirect is working as expected.

3. Advanced Website Testing with Postman

Postman offers advanced capabilities for more complex testing scenarios.

3.1. Using Variables and Environments:

  • Variables: Store dynamic values in variables to eliminate repetition in your tests. For example, you can create a variable baseUrl that holds the base URL of your website.
  • Environments: Manage different sets of variables for various testing environments (e.g., development, staging, production). Environments make it easy to switch between these testing contexts.

3.2. Running Tests and Assertions:

  • Tests: Use Postman’s built-in test runner to assert conditions within your requests. The test runner executes JavaScript code to verify specific aspects of the response.

3.3. Example Test Script:

pm.test("Status code is 200", function () {
    pm.response.to.have.status(200);
});


pm.test("Response contains 'Welcome'", function () {
    pm.expect(pm.response.text()).to.include("Welcome");
});

3.4. Creating Test Suites:

  • Organize Tests: Group multiple tests within a single request to structure your workflow. This ensures that several assertions are executed after sending a single request.

4. Real-World Example: Testing a Login Form

Let’s examine a practical example of using Postman to test a login form on a website.

4.1. Setting up the Test:

  • Create a new request: In your collection, create a POST request titled “Login.”
  • Set the URL: Enter the URL of the login form endpoint.
  • Define the Body: Provide the login credentials in the “Body” section: 
    {
        "username": "your_username",
        "password": "your_password"
    }
  • Add Tests: 
    pm.test("Status code is 200", function () {
        pm.response.to.have.status(200);
    });
    

    pm.test("Response contains 'Login Successful'", function () {
        pm.expect(pm.response.text()).to.include("Login Successful");
    });
    

    pm.test("Response contains a redirect URL", function () {
        pm.response.to.have.header("Location");
    });

4.2. Running the Test:

  • Clicking “Send” will execute the test.
  • If the tests pass, the response will indicate success, and the console will show the passed tests.
  • If any test fails, you’ll see an error message in the console indicating the failed assertions.

5. Conclusion:

Postman offers a comprehensive toolkit for testing the functionality of your website, including content fetching, form submissions, and user authentication. Its flexibility, combined with its powerful features, makes it a versatile testing tool for web developers and testers. By utilizing Postman’s capabilities effectively, you can ensure the quality and robustness of your web applications.

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