By testing on virtual machines, developers and testers can monitor how the software is performing on a specific device. Compared to real device testing, virtual testing mimics real devices and creates a virtual mobile device on a computer. The two types of programs used for virtual testing devices are emulators and simulators. Even though these terms are used interchangeably, each type comes with different capabilities and limitations.
What are Emulators?
Emulation is the process of enabling a computer system (the host) to mimic the hardware and software features of another target device (the guest). Emulators are essentially used as “substitutes”, which replaces the original device for real use.
- Emulator’s Capabilities: The emulator provides virtual device instances with near-native capabilities and extended controls to adjust the target/mobile device’s physical sensors, battery state, geolocation, and more.
- Emulator’s Limitations: In most cases, the near-native capabilities of an emulator include significant performance overhead due to binary translation. For Android apps and website testing, virtual mobile device emulators can be unreliable since they run slower than real Android devices. Because emulators cannot fully mimic real-world conditions, the testing results won’t be accurate for final releases.
What are Simulators?
Simulation is the process of modeling an environment to mimic the behavior and configuration of another target device. Compared to emulation, a simulator is used for “analysis and study”. By using a simulator, you create a virtual environment that mimics the target device from the real world. Ultimately, the simulation process shows you how the device would work in the real environment. However, a simulator doesn’t exactly follow the activity of the real environment.
- Simulator’s Capabilities: An iOS simulator sits on top of your operating system and mimics the iOS by running your app inside it. You can view this simulation in an iPhone or iPad window. Machine-language translation isn’t involved, so the iOS simulator is faster than the Android emulator.
- Simulator’s Limitations: Unfortunately, the iOS simulator can only be used on a macOS platform. This is because the simulator relies on Apple’s native Cocoa API to handle the GUI, runtime, and more. Compared to Android emulators, simulators cannot mimic battery states or cellular interrupts as well.