Is it better to conduct testing on a real device or on a simulator?

Both options have their advantages and disadvantages, and the choice depends on testing goals and available resources.

On a real device, it is better to conduct:

• Performance testing (loading speed, interface responsiveness).
• Hardware testing (camera, GPS, Bluetooth, sensors).
• Interaction testing with other applications and notifications.
• Behavior testing in real network conditions (frequent switching between Wi-Fi and mobile data, poor signal).
• User experience and usability testing in real conditions.
• Regression testing on key devices to ensure compatibility with the most popular models.

On a simulator/emulator, it is better to conduct:

• Rapid iterative testing during development (accelerates the "code-test" cycle).
• Testing on various screen sizes and resolutions.
• Basic functionality and logic testing.
• Automated testing (often easier to set up on emulators).
• Testing on OS versions that do not have physical devices.
• Code debugging (more extensive debugging capabilities).

Summary table:

Criterion	Real device	Simulator/Emulator
Accuracy of imitation	High (real hardware)	Medium (hardware emulation may differ)
Performance	Representative	May differ from real
Hardware support	Full support	Emulation, often incomplete
Network conditions	Real	Emulation, often ideal
Debugging convenience	Partially limited (may require special add-ons)	High (integrated with IDE)
Test speed	Slower due to build, install, etc.	Faster, especially for basic tests
Cost	Requires purchase and maintenance of devices	Usually free or included in IDE
OS version availability	Limited by device availability	Easily accessible multiple versions

The ideal approach is to combine testing on simulators/emulators for quick iterations and debugging with testing on real devices to check performance, hardware compatibility, and user experience.