Explain the use of Go's testing and mocking frameworks for testing and verifying the behavior and functionality of Go programs?

Go provides a built-in testing framework that allows developers to write unit tests for their code. The testing package provides a set of functions for writing tests and comparing values, such as testing.T, testing.B, and testing.M.

To write a test in Go, developers simply create a new file with a name ending in **_test.go** and write test functions with names beginning with **Test**. For example, a test function for a function named **Add** might be named **TestAdd**. Developers can then use the **testing.T** function to create test cases and verify the behavior of the **Add** function.

Go also provides a mocking framework called **gomock** that makes it easier to write unit tests for code that depends on external systems or services. **gomock** allows developers to create mock objects that simulate the behavior of these external dependencies, so that they can test their code in isolation.

To use **gomock**, developers define an interface for the external dependency they want to mock, and then use **gomock** to generate a mock implementation of that interface. They can then use this mock object in their unit tests to simulate the behavior of the real external dependency.

Overall, Go's built-in testing framework and **gomock** make it easy for developers to write robust unit tests for their code and verify its behavior and functionality.