Testing Go code

Here’s a cute way to test Go code. From How To Implement Domain-Driven Design (DDD) in Golang.

package memory

import (
  "testing"

  "ddd/aggregate"
  "ddd/domain/customer"

  "github.com/google/uuid"
)

func TestMemory_GetCustomer(t *testing.T) {
  type testCase struct {
    expectedErr error
    name        string
    id          uuid.UUID
  }

  // Create a fake customer to add to repository
  cust, err := aggregate.NewCustomer("Percy")
  if err != nil {
    t.Fatal(err)
  }
  id := cust.GetID()
  // Create the repo to use, and add some test Data to it for testing
  // Skip Factory for this
  repo := MemoryRepository{
    customers: map[uuid.UUID]aggregate.Customer{
      id: cust,
    },
  }

  testCases := []testCase{
    {
      name:        "No Customer By ID",
      id:          uuid.MustParse("f47ac10b-58cc-0372-8567-0e02b2c3d479"),
      expectedErr: customer.ErrCustomerNotFound,
    }, {
      name:        "Customer By ID",
      id:          id,
      expectedErr: nil,
    },
  }

  for _, tc := range testCases {
    t.Run(tc.name, func(t *testing.T) {
      _, err := repo.Get(tc.id)
      if err != tc.expectedErr {
        t.Errorf("Expected error %v, got %v", tc.expectedErr, err)
      }
    })
  }
}

func TestMemory_AddCustomer(t *testing.T) {
  type testCase struct {
    name        string
    cust        string
    expectedErr error
  }

  testCases := []testCase{
    {
      name:        "Add Customer",
      cust:        "Percy",
      expectedErr: nil,
    },
  }

  for _, tc := range testCases {
    t.Run(tc.name, func(t *testing.T) {
      repo := MemoryRepository{
        customers: map[uuid.UUID]aggregate.Customer{},
      }

      cust, err := aggregate.NewCustomer(tc.cust)
      if err != nil {
        t.Fatal(err)
      }

      err = repo.Add(cust)
      if err != tc.expectedErr {
        t.Errorf("Expected error %v, got %v", tc.expectedErr, err)
      }

      found, err := repo.Get(cust.GetID())
      if err != nil {
        t.Fatal(err)
      }
      if found.GetID() != cust.GetID() {
        t.Errorf("Expected %v, got %v", cust.GetID(), found.GetID())
      }
    })
  }
}

Programming