When testing mobile apps, functional validation is only half the story. A lot of critical issues surface during non-functional testing, especially in areas like interruption testing. One of the key subcategories under interruption testing is network interruption testing. Some features that work flawlessly on a strong Wi-Fi connection can slow down, fail silently, or time out when the network becomes weak or unstable.<\/p>\n
During one of our previous engagements, a colleague noticed some inexplicable failures in an app we were testing. After some digging, we discovered the real culprit: the device was on an unusually slow network. That, in turn, led us to explore reliable ways to simulate poor network conditions during testing.<\/p>\n
We wanted a practical way to test the app’s behaviour on a slow or unstable network without relying on premium tools or expensive network simulators. We tried a few apps that claimed to simulate slow networks, but the results were mixed. Some didn’t work as expected, while others required paid versions to unlock throttling features.<\/p>\n
Since I am using an Ubuntu machine, this post focuses on how to simulate slow network conditions on a Linux-based system. On Windows, you may need to use a third-party tool (e.g., NetLimiter or Clumsy) to throttle the network, as we are not aware of a built-in tool like Traffic Control. Let us know in the comments if you know of one.<\/p>\n
Most laptops cannot use the same Wi-Fi card to both connect to a Wi-Fi network and broadcast a hotspot at the same time. This means that when you enable a hotspot, your existing Wi-Fi connection will disconnect.<\/p>\n
The simplest setup is to use a wired (Ethernet) connection for internet while your Wi-Fi card handles the hotspot.<\/p>\n
If you don’t have Ethernet, you can use one of the following alternatives:<\/p>\n
* A USB Wi-Fi adapter (use one adapter for Wi-Fi, and the built-in adapter for the hotspot)<\/p>\n
* USB tethering from your phone to provide internet to your laptop, and then create the hotspot from the laptop<\/p>\n
To create a hotspot from your Ubuntu system:<\/p>\n
1. Go to Settings\/Wi-Fi
\n2. Turn on Wi-Fi Hotspot
\n3. Set your Network Name and Password
\n4. Connect your mobile device to this newly created hotspot<\/p>\n
Once connected, your phone’s internet traffic flows through your Ubuntu system, allowing you to control and throttle the network speed from your laptop. Ubuntu includes a built-in tool called tc (Traffic Control)<\/a> that lets you simulate slow, unstable, or high-latency networks without installing anything extra. This is the method we used.<\/p>\n First, find the interface that your hotspot is using:<\/p>\n Look for the active Wi-Fi interface. (For example, on my system it was wlp0s20f3.)<\/em><\/p>\n Here’s an example of limiting bandwidth and adding latency:<\/p>\n This sets: You can adjust these values based on the network condition you want to test.<\/p>\n When you’re done testing:<\/p>\n There you have it. Once you apply the tc<\/em> rules, your Ubuntu system will slow down the network on the hotspot. Any device connected to it, including your phone, will experience the reduced speeds and added latency. This gives you a practical way to observe how your app behaves when the network isn’t ideal.<\/p>\n Real-world networks are messy, and app behaviour changes drastically under stress. Setting up a controlled slow network on Ubuntu turned out to be a quick, practical way to test these scenarios. It doesn’t replace full-scale network simulators, but it’s more than enough for everyday testing. Hopefully this walkthrough helps you bring more realistic network checks into your workflow.<\/p>\n Many teams assume that testing in real-world conditions is just about using the app the way a user would. But as QA engineers, we need to go a step further, we must recreate those conditions intentionally, control them, and make the tests repeatable. That’s where thoughtful techniques like network throttling really add value.<\/p>\n At Qxf2, we specialize in designing practical, repeatable tests for messy real-world scenarios like slow networks, interruptions, unpredictable environments, and more. If you need help bringing this level of depth into your testing workflow, reach out<\/a>. We enjoy the technical challenges others overlook.<\/p>\n When testing mobile apps, functional validation is only half the story. A lot of critical issues surface during non-functional testing, especially in areas like interruption testing. One of the key subcategories under interruption testing is network interruption testing. Some features that work flawlessly on a strong Wi-Fi connection can slow down, fail silently, or time out when the network becomes […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[71],"tags":[],"class_list":["post-23385","post","type-post","status-publish","format-standard","hentry","category-mobile-automation"],"_links":{"self":[{"href":"https:\/\/qxf2.com\/blog\/wp-json\/wp\/v2\/posts\/23385","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/qxf2.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/qxf2.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/qxf2.com\/blog\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/qxf2.com\/blog\/wp-json\/wp\/v2\/comments?post=23385"}],"version-history":[{"count":20,"href":"https:\/\/qxf2.com\/blog\/wp-json\/wp\/v2\/posts\/23385\/revisions"}],"predecessor-version":[{"id":23448,"href":"https:\/\/qxf2.com\/blog\/wp-json\/wp\/v2\/posts\/23385\/revisions\/23448"}],"wp:attachment":[{"href":"https:\/\/qxf2.com\/blog\/wp-json\/wp\/v2\/media?parent=23385"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/qxf2.com\/blog\/wp-json\/wp\/v2\/categories?post=23385"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/qxf2.com\/blog\/wp-json\/wp\/v2\/tags?post=23385"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nIf you’re on Windows, you can follow this guide: How to Turn Your Windows PC Into a Wi-Fi Hotspot<\/a><\/p>\n
\nStep 3: Throttle network speed using tc (Traffic Control)<\/h4>\n
1. Identify your Wi-Fi interface<\/h5>\n
\r\nip link show\r\n<\/pre>\n
2. Apply throttling (simulate slow network)<\/h5>\n
\r\nsudo tc qdisc add dev wlp0s20f3 root tbf rate 128kbit burst 16kbit latency 600ms\r\n<\/pre>\n
\n* Speed: 128 kbps
\n* Burst buffer: 16 kb
\n* Latency: 600 ms<\/p>\n3. Remove throttling (restore normal speed)<\/h5>\n
\r\nsudo tc qdisc del dev wlp0s20f3 root\r\n<\/pre>\n
\n Conclusion<\/h3>\n
\n Need help going beyond “real-world” testing? Contact Qxf2<\/h3>\n
\n","protected":false},"excerpt":{"rendered":"