Hands-On Dependency Injection in Go

Monkey patching with SQLMock

Firstly, a quick refresher: currently, the data package does not use DI, and therefore we cannot pass in the *sql.DB like we did in the previous example. The function currently looks as shown in the following code:

// Save will save the supplied person and return the ID of the newly // created person or an error.// Errors returned are caused by the underlying database or our connection// to it.func Save(in *Person) (int, error) {   db, err := getDB()   if err != nil {      logging.L.Error("failed to get DB connection. err: %s", err)      return defaultPersonID, err   }   // perform DB insert   query := "INSERT INTO person (fullname, phone, currency, price) VALUES (?, ?, ?, ?)"   result, err := db.Exec(query, in.FullName, in.Phone