How can I use mock objects in my Go tests?

How can I use mock objects in my Go tests?

You can use libraries like 'gomock' or 'testify' to create mock objects in Go tests. Would you like a code example?

Yes, please provide a code example using 'gomock'.

Sure! First, install 'gomock' and 'mockgen'. Then, create an interface for the object you want to mock. Here's a simple example:

// Define the interface
type Database interface {
    GetUser(id string) (*User, error)
}

// Generate the mock using mockgen
// mockgen -source=yourfile.go -destination=mock_database.go -package=mypackage

// In your test file
func TestGetUser(t *testing.T) {
    mockDB := &MockDatabase{}
    mockDB.On("GetUser", "123").Return(&User{Name: "John"}, nil)

    // Call the function that uses the mock
    user, err := GetUser(mockDB, "123")
    // Assert the results
}

This way, you can test your functions without relying on a real database.

That makes sense! How do I assert that the mock was called?

You can use the AssertExpectations method provided by 'testify'. After your test, just call mockDB.AssertExpectations(t) to verify that the expected methods were called.