Testing in Unreal Engine projects is not a one-size-fits-all problem. As projects grow in size, complexity, and team distribution, so do the expectations for test automation to solve previously encountered roadblocks, interruptions, or failed tests. Moreover, test automation not only brings more fluidity to the testing process but also ensures much-needed reliability before every release (internal or to production).
Unreal Engine provides its own native testing frameworks, while tools like AltTester® approach the problem from a different angle, focusing on end-to-end automation on real game builds – this goes from testing the game itself, with all its functions, to testing adjacent app-related actions like login to a backend, achievements, leaderboards, or integrating third-party SDKs (eg., SteamSDK, EpicOnlineServices etc.).
In this article, we’ll take a pragmatic look at Unreal Engine’s built-in test frameworks compared to AltTester®, highlighting where each one shines, where each has limitations, and why many Unreal teams could choose to combine them rather than replace one with the other.
Our goal is simple: help Unreal developers and testers who might be hesitant to adopt an additional testing framework understand what AltTester® adds to an Unreal-based project, especially when scalability, team structure, and long-term automation strategy are at stake.
Who this article is written for
Before going any further, it’s worth being clear about who we’re writing this for. This article is for Unreal developers, QA leads, or technical decision-makers who find themselves at any of these stages:
- You haven’t started testing yet, but you’re feeling the pressure to — from growing complexity, faster releases, or an expanding team
- You’re using Unreal’s native testing frameworks and wondering whether they’re enough
- You’ve built something internally and are starting to feel the maintenance cost creep in
- You work with external QA partners, distributed teams, or automation engineers who aren’t Unreal specialists
- You’re looking for a more sustainable automation strategy as your project scales
Whether testing is already part of your workflow or still something you’re figuring out, this article is meant to give you a practical frame for thinking about it.
A quick overview: Unreal Engine testing frameworks
Unreal Engine ships with several native testing options, each designed for specific layers of testing:
1. Simple & complex automation tests
These are primarily unit-style tests written in C++.
Strengths
- Great for validating isolated logic and free functions
- Fast execution
- Tight integration with Unreal’s codebase
Limitations
- No level or gameplay context is loaded
- Available only in C++
- Not suitable for testing real player flows or interactions
These tests are excellent for implementation-level confidence, but they don’t tell you much about how the game behaves from a player’s perspective.
2. Spec tests
Spec tests introduce minimal state and sequencing, allowing latent actions and basic flows.
Strengths
- Support setup and cleanup logic
- Can simulate small workflows (e.g., login, inventory updates)
- Still fast and deterministic
Limitations
- No real project map is loaded
- Actors must be manually spawned
- C++ only
Spec tests sit somewhere between unit tests and gameplay tests, but they still stop short of validating actual in-level behavior.
3. Functional tests
Functional tests are Unreal’s closest native equivalent to gameplay testing.
Strengths
- Run inside real levels
- Can reference pre-placed actors
- Available in both C++ and Blueprints
Limitations
- Tests live inside levels and must be managed carefully
- Removed before packaging
- Tightly coupled to the project structure
Functional tests are powerful, but they are also deeply embedded in the Unreal project itself, which can become a challenge as teams scale or involve external QA.
Where AltTester® approaches testing differently
AltTester® is not designed to replace Unreal’s internal testing tools or convince a single team to suddenly test everything in different places. Its real advantage is allowing the QA team to focus on end-to-end automation on the actual game build, the same artifact that reaches players, publishers, or certification teams. Unreal’s native tools are excellent when you are close to the code. AltTester® comes in when the game needs to be tested as it actually ships.
To explain further, here is what makes AltTester® fundamentally different.
Let’s explore some of the key benefits of AltTester®’s test framework:
1. Full object visibility, even in packaged games
Inside the Unreal Editor, developers rely heavily on the World Outliner and object hierarchy to understand what’s happening in a scene: what spawned, where it is, what state it’s in, and which properties changed.
Once the game is packaged, that visibility usually disappears.
At that point, teams often fall back to:
- Adding temporary logs for specific objects or states
- Enabling fly mode and manually searching for actors
- Guessing whether something failed to spawn or is simply invisible
AltTester® changes this by exposing the object hierarchy, properties, materials, and methods, even when working with already packaged builds.
This means:
- Engineers can inspect any object or actor just by clicking on it
- You can verify what actually spawned, where it is located, and which properties it has at runtime
- Issues like typos, incorrect materials, broken transitions, or wrong states are easier to spot
- Developers and testers can debug problems directly in the running game, without rebuilding or re-instrumenting
For Unreal teams used to editor-level visibility, this is a big shift. It brings a familiar debugging workflow into packaged builds and drastically shortens the feedback loop between discovering an issue and fixing it.
2. Built-in input simulation
AltTester® includes a ready-to-use user input simulation:
- Swipe
- Hold
- Drag and drop
- Other common gestures
Too many teams spend too much time implementing their own input simulation library. There’s no need to build and maintain a custom input simulation layer inside Unreal. This alone can save significant engineering effort, especially for cross-platform projects.
Just as importantly, AltTester® keeps test logic decoupled from the game code. Tests can live in their own repository, can be updated independently, and don’t require reinstrumenting the game when scenarios change, making it much easier to evolve automation without touching build pipelines.
3. End-to-end validation beyond the game itself
AltTester® supports end-to-end automation that extends beyond the game’s internal logic to cover these adjacent layers:
- Backend login and authentication flows – validate that a player can sign in, that sessions behave correctly, and that failures are handled gracefully
- Achievements and leaderboards – test that in-game actions correctly trigger backend updates and that data is returned and displayed as expected
- Third-party SDK integrations – verify that integrations like SteamSDK or EpicOnlineServices behave correctly in the packaged build, not just in development environments
This matters because these are exactly the kinds of issues that tend to surface late – often during certification or after launch – precisely because they’re invisible to engine-level tests. AltTester® makes it possible to catch them earlier, on the same builds your certification and QA teams are already testing.
Team with in-house or external QA?
Many Unreal projects don’t rely only on an in-house QA team embedded in the engine. They also work with external QA vendors, testing studios, or distributed partners who validate builds without touching the Unreal project itself.
In those setups, asking every tester to pull hundreds of gigabytes and compile the source code, and then learn engine-specific workflows, simply isn’t realistic. And it usually slows everyone down.
AltTester® is designed with this exact reality in mind, because we allow both creating & running tests directly on the packaged build.
Accessible to non-Unreal automation engineers
AltTester® follows common test automation paradigms and supports multiple languages, including Python, C#, and Java.
This means:
- QA engineers don’t need deep Unreal Engine knowledge
- Teams can reuse existing automation expertise
- Non-gaming automation engineers can transition faster
For teams familiar with Selenium or Appium, AltTester® feels conceptually familiar, lowering onboarding costs.
Test the real game build, without Unreal Editor access
With AltTester®, QA engineers can:
- Write and run automated tests without needing to open or operate the Unreal Editor
- Run tests without needing direct access to the game’s source code
In practice, this means automation can run against the same packaged builds that internal teams, QA, or stakeholders already test manually.
Not having to use the Unreal Editor reduces significant setup, engine-specific knowledge, and project coupling. Not requiring access to source code makes it much easier to involve external QA vendors or central automation teams without changing repository access rules.
This becomes especially valuable as internal releases become more frequent.
At that stage, teams usually split focus:
- QA starts validating new gameplay, features, and fixes
- Automated tests focus on regression coverage for previously implemented functionality
AltTester® supports this workflow naturally. Regression suites can run continuously on fresh builds, while testers explore what’s new, without forcing everyone into the engine or slowing down iteration.
Because tests run against packaged builds and live outside the game repository, CI/CD pipelines stay stable even as test coverage grows. Teams can expand regression coverage over time without introducing risk into the build process itself.
Unreal tests vs AltTester®: it’s not either-or
Unreal’s native test frameworks excel at:
- Low-level validation
- Engine-specific logic
- Fast developer feedback
AltTester® excels at:
- End-to-end gameplay validation
- Black-box testing of real builds
- Cross-team and external QA collaboration
In practice, the strongest testing strategies combine both approaches:
- Use Unreal’s frameworks for unit, spec, and internal functional tests
- Use AltTester® to validate player flows, regressions, and real-world behavior on packaged builds
Why Unreal teams adopt AltTester®
For Unreal developers hesitant to introduce another framework, the key question is usually: Is it worth it?
Teams adopt AltTester® because it:
- Reduces time-to-feedback
- Makes automation accessible beyond Unreal specialists
- Scales better with distributed and external QA
- Supports long-term regression strategies on real builds
And ultimately, it helps teams ship with more confidence, without replacing the tools they already rely on.
Who should use what? (A practical way to think about it)
If you’re wondering whether you really need another testing framework alongside Unreal’s, here’s a simple way teams usually decide:
Unreal Engine native tests are a great fit if:
- You’re validating low-level logic or engine-side behavior
- Your tests live close to the code and are written by Unreal developers
- You need fast feedback during development, before anything is packaged
AltTester® is a great fit if:
- You care about how the game behaves as a player experiences it
- You want reliable regression tests on real, packaged builds
- Your QA team (internal or external) isn’t deeply familiar with Unreal
- You’re scaling automation across platforms, teams, or studios
Most mature Unreal teams don’t choose one over the other. They use Unreal’s tools to keep the foundations solid, and AltTester® to make sure nothing breaks once the game actually leaves the engine.
Final thoughts
If you’re already using Unreal’s testing frameworks, you’re doing the right thing. They’re powerful, flexible, and deeply integrated into the engine. But they were never meant to cover every testing scenario a real production team runs into.
AltTester® isn’t about replacing what you already have; it’s about covering the gaps that show up later: real builds, real player flows, regression safety, and teams that extend beyond Unreal specialists.
For many studios, the moment AltTester® starts to make sense is when automation needs to scale beyond the core dev team, when QA, external partners, or CI pipelines need to test the game as it actually ships. If that sounds familiar, adding AltTester® to your Unreal workflow usually isn’t a big leap. It’s a practical one. And over time, it tends to pay off most when you’re running stable, repeatable tests against the same builds your players will touch.