API Test Script

An API Test Script is a set of instructions or code written to test the functionality, reliability, performance, and security of an Application Programming Interface (API). These scripts simulate API calls and verify the responses against expected outcomes to ensure that the API behaves as intended.

🔍 Purpose of API Test Script

• To automate the process of sending requests and validating responses.
• To check if the API:
  • Returns correct status codes.
  • Provides accurate data in the response body.
  • Responds within acceptable time limits.
  • Handles errors properly (like invalid input or missing authentication).

Components of an API Test Script

• Request Setup:
  • Endpoint URL (e.g., https://api.example.com/users)
  • HTTP Method (GET, POST, PUT, DELETE)
  • Headers (e.g., Content-Type, Authorization)
  • Request Body (for POST/PUT)
• Execution:
  • Sending the API request using a tool or code.
• Assertions / Validations:
  • Verify the response status (e.g., 200 OK, 404 Not Found)
  • Validate response body data
  • Check response time
  • Assert headers or cookies if needed

🛠️ Example (Using Postman Test Script):

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

pm.test("Response time is less than 500ms", function () {
 pm.expect(pm.response.responseTime).to.be.below(500);
});

pm.test("Check user ID in response", function () {
 var jsonData = pm.response.json();
 pm.expect(jsonData.id).to.eql(101);
});

Tools Used for API Test Scripting

Some common tools used for API test scripts are as follows:

• Postman (with JavaScript-based tests)
• Rest Assured (Java)
• SoapUI (Groovy scripting)
• JUnit/TestNG + HTTP client libraries
• Python + requests + unittest/pytest
• JMeter, Karate, Cypress, etc.

📌 Summary

An API Test Script automates the testing of APIs by sending requests and checking responses against expected results, helping developers and testers ensure API quality and functionality.