Why HTTP methods define API intent in Postman - Test Execution Impact

Test Overview

This test sends requests using different HTTP methods (GET, POST, PUT, DELETE) to an API endpoint. It verifies that the API responds correctly according to the intent of each HTTP method.

Test Code - Postman

Postman

pm.test("GET request returns 200 and data", function () {
    pm.sendRequest({
        url: pm.environment.get("apiUrl") + "/items",
        method: 'GET'
    }, function (err, res) {
        pm.expect(err).to.eql(null);
        pm.expect(res).to.have.property('code', 200);
        pm.expect(res.json()).to.be.an('array');
    });
});

pm.test("POST request creates new item", function () {
    pm.sendRequest({
        url: pm.environment.get("apiUrl") + "/items",
        method: 'POST',
        header: {'Content-Type': 'application/json'},
        body: {
            mode: 'raw',
            raw: JSON.stringify({name: "NewItem"})
        }
    }, function (err, res) {
        pm.expect(err).to.eql(null);
        pm.expect(res).to.have.property('code', 201);
        pm.expect(res.json()).to.have.property('name', 'NewItem');
    });
});

pm.test("PUT request updates existing item", function () {
    pm.sendRequest({
        url: pm.environment.get("apiUrl") + "/items/1",
        method: 'PUT',
        header: {'Content-Type': 'application/json'},
        body: {
            mode: 'raw',
            raw: JSON.stringify({name: "UpdatedItem"})
        }
    }, function (err, res) {
        pm.expect(err).to.eql(null);
        pm.expect(res).to.have.property('code', 200);
        pm.expect(res.json()).to.have.property('name', 'UpdatedItem');
    });
});

pm.test("DELETE request removes item", function () {
    pm.sendRequest({
        url: pm.environment.get("apiUrl") + "/items/1",
        method: 'DELETE'
    }, function (err, res) {
        pm.expect(err).to.eql(null);
        pm.expect(res).to.have.property('code', 204);
    });
});

Execution Trace - 4 Steps

Step	Action	System State	Assertion	Result
1	Send GET request to /items endpoint	API server is running and has items data	Response code is 200 and response body is an array	PASS
2	Send POST request to /items with new item data	API server accepts new item creation	Response code is 201 and response body contains the new item name	PASS
3	Send PUT request to /items/1 to update item name	API server updates item with id 1	Response code is 200 and response body contains updated item name	PASS
4	Send DELETE request to /items/1 to remove item	API server deletes item with id 1	Response code is 204 with no content	PASS

Failure Scenario

Failing Condition: API returns unexpected status code or response body does not match expected for HTTP method

Execution Trace Quiz - 3 Questions

What HTTP method is used to retrieve data without changing it?

A GET

B POST

C PUT

D DELETE

Key Result

Using the correct HTTP method clearly communicates the API's intent, making tests easier to understand and ensuring the API behaves as expected.