Applying monkey patching

Let's apply monkey patching to our ACME registration service that we introduced in Chapter 4, Introduction to ACME Registration Service. One of the many things we would like to improve with our service is the test reliability and coverage. In this case, we will be working on the data package. Currently, we only have one test, and it looks like this:

func TestData_happyPath(t *testing.T) {
   in := &Person{
      FullName: "Jake Blues",
      Phone:    "01234567890",
      Currency: "AUD",
      Price:    123.45,
   }

   // save
   resultID, err := Save(in)
   require.Nil(t, err)
   assert.True(t, resultID > 0)

   // load
   returned, err := Load(resultID)
   require.NoError(t, err)

   in.ID = resultID
   assert.Equal(t, in, returned)
   
   // load all
   all, err := LoadAll()
   require.NoError(t, err)
   assert.True(t, len(all)...