Definitely, I am writing an assignment for you which you can solve. This is what I was asked to complete in my CA test:
Open any E-Commerce website.
Search for a keyword on the home page.
On the results page, select a product.
On the details page, add the product to the cart.
Now go to the cart.
Check out as a not-registered user.
Continue the order placement process to the last page.
Now submit the order with an invalid credit card so that an error is generated.
Log the error details.
In the test, I was supposed to build a full project for this including the test automation framework. Do let me know if you have any questions. If you are new to the Selenium then do enrol into the following Selenium Training Course. If can also read the following Selenium Tutorial. Here is a video tutorial which you can watch into clear all your concepts regarding Selenium. .