What are the levels of testing in embedded systems?

Embedded systems are used in a variety of devices, from cars to medical equipment, and as such require thorough testing to ensure they function correctly. There are several levels of testing in embedded systems.
The first level is unit testing, which tests individual components of the system to ensure they function properly.
Integration testing is the next level, which tests how well the individual components work together.
System testing is the third level, which tests the system as a whole to ensure it meets the specified requirements.
Regression testing is performed when changes are made to the system to ensure that the changes did not negatively impact previously tested functionality.
Acceptance testing is the last level, which tests the system against the customer's requirements to ensure it meets their needs.
Each level of testing is important in ensuring that the embedded system is reliable, efficient, and meets the requirements of those who will be using it.