Appium is a popular open source test automation tool for controlling a native, hybrid, or mobile app on iOS mobile, Android mobile, and Windows desktop platforms. It allows testers and developers to create automated tests of mobile applications, helping them deliver quality software faster, with less risk.
An emulator, as the term suggests, emulates the device software and hardware on a desktop PC, or as part of a cloud testing platform. It is a complete re-implementation of the mobile software written in a machine level assembly language. The Android (SDK) emulator is one such example.
A simulator delivers a replica of a phone’s user interface and does not represent its hardware. A simulator is a partial re-implementation of the operating system written in a high-level language. The iOS simulator for Apple devices is one such example.
Emulators and simulators enable parallel testing in a way that can’t be achieved with devices in a lab. Because tests on emulators and simulators are software-defined, multiple tests can be run on tens of emulators and simulators at the click of a button without having to manually prepare each emulator/simulator for the tests.
Emulators and simulators are complementary to real devices, but they can’t deliver the real-world environment that a device can deliver. Real devices and virtual devices (emulators/simulators), when used together in an automated testing environment, enable modern mobile development and testing teams to get the most out of their mobile testing efforts.