What I learned about “Memory Leaks” – a small reminder that changed my testing mindset

If you’ve ever worked as a Web tester before moving to Mobile App testing, you may have felt the same thing I did:

• Web runs smoothly → everything seems fine
• The browser cleans up RAM automatically → no big worries
• A heavy tab? → just close it

And then… I moved to Mobile App testing.
That was when I kept hearing developers and PMs say:

“Memory Leak.”

Back then, I honestly didn’t know what it really meant. I thought it was just “technical stuff” that I, as a tester, didn’t need to care about.

It’s funny how our minds work –
If we don’t understand something, we label it as “hard”…
And if it sounds technical, we assume “it’s probably not my problem.”

But one day, a simple question from my PM completely changed how I think about mobile testing.

A small question that opened my eyes

After a daily meeting, our PM stayed behind and casually asked our test team:

“Have you ever tested what happens when the app runs overnight and you continue using it the next morning?”
“Web testers who switch to Mobile often forget this.”

I was genuinely surprised.
Not because the question was difficult –
but because I had never even thought about it.

And it turned out I wasn’t alone.
Everyone on the test team (even those experienced in Mobile) admitted:

• We only tested the app for a few hours
• None of us had ever left an app running overnight
• We never asked: “What happens after 8 or 10 hours of continuous use?”
• And we had no test case for this scenario

That moment made me realize:

Mobile testing isn’t just about “functions working.”
It’s also about “how long the app can survive.”

Mobile Devices Have Limited Resources — and They Break Easily

A memory leak happens when:

1. The app uses RAM to do something
2. But forgets to free that memory afterward
3. RAM keeps filling up
4. The app gets slower → freezes → crashes
5. The operating system kills it

This happens when developers forget to release memory after:

• Opening/closing screens
• Loading images
• Scrolling long lists
• Using the camera
• Playing video
• Switching between apps

That’s why memory leaks are time-based bugs.
The longer you use the app, the worse it gets.

A simple visual example

Imagine RAM like cups of water.

• The app pours water (memory) into a cup to work
• When done, it should empty the cup
• But if the cup is never emptied…

Eventually all cups fill up → no cup left → app crashes.

A practical checklist for testing Memory Leaks

Below is an expanded version of the checklist I used.
You can apply it immediately, even without advanced tools.

Repeated action test (perform 20–30 times)

Try repeating actions that often consume memory:

• Open → close a screen repeatedly
• Scroll long lists
• Open → close popups
• Upload files multiple times
• Take many photos in a row

What to observe:

• Does the app slowly become laggy?
• Do animations start jerking?
• Does rendering become slower?

These are signs of early-stage memory leaks.

Long-running usage test (overnight test)

This is the simplest but most overlooked test:

1. Open the app
2. Leave it running overnight
3. Use it again the next morning

Check if:

• The app restarted itself
• The OS killed the app
• The app is still open but extremely laggy

This one test alone has revealed many issues in our team.

Background mode test (running in the background)

Mobile apps suffer memory leaks even more when running in the background.

Try:

• Open the app
• Press Home
• Use other apps for a few hours
• Return to the app

Check if:

• The app reloads from the start
• The app freezes
• The app crashes

Any of these can indicate memory leaks.

Why This Matters: Testing Mobile = Testing Time + Resources

Testing a mobile app for only 1–2 hours is like:

Starting a new car for 5 minutes and declaring it “perfectly fine.”

Memory leaks don’t appear immediately.
They appear through repetition, duration, and real usage.

And thanks to that small question from my PM, I finally understood one truth:

A tester’s job is not only to ensure features work.
It’s also to protect the long-term health of the application.

Final thoughts

Memory leaks may sound technical, but understanding them doesn’t require deep coding knowledge.
What matters is knowing how to test them and why they matter for real users.

So if you’re a Mobile App tester, ask yourself:

• “Have I tested the app after 8–12 hours?”
• “Have I tested long scrolling, camera usage, background mode?”
• “Have I tested how the app behaves after days of use?”

If not, today is a great day to start.

References

Fundamentals of Mobile Testing – GeeksforGeeks

Mobile App Testing Guide: Types, Tools & Best Practices

Mobile App Testing Tutorial

Mobile Testing Tutorial