How to use the Go unit testing tool gomonkey?

gomonkey is a tool used for mocking Go functions, allowing you to replace the implementation of functions in unit tests. Here is the basic usage of gomonkey:

1. To begin with, install the gomonkey module.

go get github.com/agiledragon/gomonkey

1. Import the gomonkey module.

import (
    "github.com/agiledragon/gomonkey"
)

1. Create a new gomonkey instance in the test function.

monkey := gomonkey.NewMonkey()

1. Use the monkey.patch method to replace the implementation of a function, for example:

monkey.Patch(math.Sqrt, func(float64) (float64, error) {
    return 1.0, nil
})

The code above will replace the implementation of the math.Sqrt function to return a fixed value of 1.0.

1. Test the modified function in the test function, and remember to restore the implementation of the function after testing.

defer monkey.Unpatch()

By following these steps, you can use the gomonkey tool to mock Go functions for easier unit testing.