enable to mock database (#98)

Signed-off-by: Felipe Oliveira <felipeweb.programador@gmail.com>

adapters/postgres/connection/conn.go

@@ -3,6 +3,8 @@ package connection
 import (
 	"fmt"
 
+	"database/sql"
+
 	"github.com/jmoiron/sqlx"
 	"github.com/nuveo/prest/config"
 	// Used pg drive on sqlx
@@ -18,7 +20,7 @@ var (
 // MustGet get postgres connection
 func MustGet() *sqlx.DB {
 	if db == nil {
-		cfg := config.Prest{}
+		cfg = config.Prest{}
 		config.Parse(&cfg)
 		dbURI := fmt.Sprintf("user=%s dbname=%s host=%s port=%v sslmode=disable", cfg.PGUser, cfg.PGDatabase, cfg.PGHost, cfg.PGPort)
 		if cfg.PGPass != "" {
@@ -33,3 +35,8 @@ func MustGet() *sqlx.DB {
 	}
 	return db
 }
+
+// SetNativeDB enable to override sqlx native db
+func SetNativeDB(native *sql.DB) {
+	db.DB = native
+}

adapters/postgres/connection/conn_test.go

@@ -2,6 +2,8 @@ package connection
 
 import (
 	"testing"
+
+	sqlmock "github.com/DATA-DOG/go-sqlmock"
 )
 
 func TestMustGet(t *testing.T) {
@@ -17,3 +19,19 @@ func TestMustGet(t *testing.T) {
 		t.Errorf("expected no error, but got: %v", err)
 	}
 }
+
+func TestSetNativeDB(t *testing.T) {
+	t.Log("Open connection")
+	db := MustGet()
+	if db == nil {
+		t.Errorf("expected db connection, but no was!")
+	}
+	mockedDB, _, err := sqlmock.New()
+	if err != nil {
+		t.Errorf("expected no error, but got: %v", err)
+	}
+	SetNativeDB(mockedDB)
+	if db.DB != mockedDB {
+		t.Errorf("expected same memory address, but no was! %v %v", db.DB, mockedDB)
+	}
+}