Example for blog post: Go bits: Magic with functions

closures_test.go

package closures_test

import (
   "testing"

   "github.com/matryer/is"

   . "go-bits/magic-with-functions/closures"
)

func Test_object_with_receiver_method_as_closure(t *testing.T) {
   // ARRANGE
   shouldBe := is.New(t)

   repo := NewFileBasedCustomerRepository()

   // the repo from above is a property of the CustomerService struct
   // which is "enclosed" in the method closures below
   service := NewCustomerService(repo)

   // this is a receiver method used as a value
   register := service.Register

   // we are passing this method as a closure
   registrationHandler := NewCustomerRegistrationHTTPHandler(register)

   // this is a receiver method used as a value
   remove := service.Remove

   // we are passing this method as a closure
   removalHandler := NewCustomerRemovalHTTPHandler(remove)

   // ACT
   registerErr := registrationHandler.Handle("John Doe")

   // ASSERT
   shouldBe.NoErr(registerErr)

   // CLEAN UP
   removalErr := removalHandler.Remove(CustomerID{Value: "123435"})
   shouldBe.NoErr(removalErr)
}