How can I mock external APIs in Go for testing?

How can I mock external APIs in Go for testing?

You can use libraries like httptest or gomock to create mock servers or interfaces for your external APIs.

Can you show me a simple example using httptest?

Sure! You can create a mock server like this:

package main

import (
    "net/http"
    "net/http/httptest"
    "testing"
)

func TestMyAPI(t *testing.T) {
    // Create a mock server
    server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        w.WriteHeader(http.StatusOK)
        w.Write([]byte(`{"message": "success"}`))
    }))
    defer server.Close()

    // Use server.URL as the API endpoint in your tests
}

What about using gomock? How does that work?

With gomock, you define an interface for your API and generate a mock implementation. Here's a brief example:

1. Define your interface:

type APIClient interface {
    GetData() (string, error)
}

2. Generate the mock using mockgen and use it in your tests.

Are there any best practices for mocking APIs in Go?

Yes! Some best practices include keeping your mocks simple, ensuring they mimic real API behavior, and using dependency injection to make testing easier.