Workflow sequencing in Postman - Build an Automation Script

Verify API workflow sequencing for user registration and login

Preconditions (3)

Step 1: Send POST request to /register endpoint with valid user data

Step 2: Verify response status code is 201 Created

Step 3: Extract user ID from registration response

Step 4: Send POST request to /login endpoint with registered user credentials

Step 5: Verify response status code is 200 OK

Step 6: Verify response contains authentication token

✅ Expected Result: User registration succeeds with status 201, login succeeds with status 200, and authentication token is returned

Automation Requirements - Postman with JavaScript tests

Assertions Needed:

Status code is 201 for registration

Status code is 200 for login

Authentication token exists in login response

Best Practices:

Use environment variables to store and reuse user ID and token

Use pm.expect assertions for validation

Chain requests using Postman collection runner or scripts

Handle asynchronous requests properly

Automated Solution

Postman

/* Registration Request Test Script */
pm.test("Registration status code is 201", function () {
    pm.response.to.have.status(201);
});

// Save user ID from registration response
const jsonData = pm.response.json();
pm.environment.set("userId", jsonData.id);

/* Login Request Pre-request Script */
// Use stored user credentials
pm.variables.set("email", "[e-mail]");
pm.variables.set("password", "TestPass123");

/* Login Request Test Script */
pm.test("Login status code is 200", function () {
    pm.response.to.have.status(200);
});

pm.test("Authentication token is present", function () {
    const jsonData = pm.response.json();
    pm.expect(jsonData).to.have.property('token');
    pm.environment.set("authToken", jsonData.token);
});

The first part tests the registration response status code is 201, which means the user was created successfully. It extracts the user ID from the JSON response and saves it in an environment variable for reuse.

The login request uses stored user credentials. The test script verifies the login response status code is 200, indicating success, and checks that the response contains an authentication token. The token is saved for future requests.

This approach ensures the workflow sequence is automated: register first, then login using the registered user data. Using environment variables allows data sharing between requests. Assertions with pm.expect validate the expected outcomes.

Common Mistakes - 3 Pitfalls

Not waiting for registration response before sending login request

Hardcoding user data in multiple requests

Not checking response status codes before extracting data

Bonus Challenge

Now add data-driven testing with 3 different user registrations and logins

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