Since Magento 1.4 is pretty outdated and doesn’t have built-in automation support, you’ll need to build your own test framework using something like Selenium. Magento Test Framework (MTF) only works for Magento 2, so it won’t help here.

Here’s a simple approach:

Use Selenium – Write test scripts in Java, Python, or PHP to automate stuff like adding items to the cart, checking out, and logging in. Pick a Testing Framework – If you're using Java, go for TestNG. If you're using PHP, try PHPUnit. These will help manage your test cases better. Make It Modular – Instead of repeating code, create reusable functions (e.g., a function for logging in, another for adding items to the cart). This will save you tons of time later. Get Help from the Magento Community – People on Magento forums have faced the same issue. You might even find existing scripts to tweak for your setup. Yes, it’ll take some effort to set up, but once it’s running, you’ll save a ton of time on testing. If you need something more plug-and-play, you might want to look at third-party tools, but custom automation is the best long-term solution.