From fb65f6708c82f9b87e8ce36fa5c049197665293f Mon Sep 17 00:00:00 2001
From: Ian Tan <ian.tan@techinasia.com>
Date: Thu, 16 Nov 2017 18:40:49 +0800
Subject: [PATCH] Groundwork for TestHelper

---
 gorm_expect.go      | 108 ++++++++++++++++++++++++++++++++++++++++++++
 gorm_expect_test.go |  26 +++++++++++
 2 files changed, 134 insertions(+)
 create mode 100644 gorm_expect.go
 create mode 100644 gorm_expect_test.go

diff --git a/gorm_expect.go b/gorm_expect.go
new file mode 100644
index 00000000..4c29231f
--- /dev/null
+++ b/gorm_expect.go
@@ -0,0 +1,108 @@
+package gorm
+
+import (
+	"database/sql"
+	"fmt"
+
+	"gopkg.in/DATA-DOG/go-sqlmock.v1"
+)
+
+// TestHelper is the exported struct used for setting expectations
+type TestHelper struct {
+	gormDb   *DB
+	mockDb   *sql.DB
+	asserter Asserter
+}
+
+func (h *TestHelper) ExpectFirst(model interface{}) Query {
+	fmt.Printf("Expecting query: %s", "some query\n")
+	return h.asserter.Query("some sql")
+}
+
+func (h *TestHelper) ExpectFind(model interface{}) {
+	fmt.Println("Expecting query: %s", "some query involving Find")
+}
+
+type Query interface {
+	Return(model interface{}) Query
+}
+
+type SqlmockQuery struct {
+	query *sqlmock.ExpectedQuery
+}
+
+func (q *SqlmockQuery) getRowsForOutType(out interface{}) *sqlmock.Rows {
+	rows := sqlmock.NewRows([]string{"column1", "column2", "column3"})
+	rows = rows.AddRow("someval1", "someval2", "someval3")
+
+	return rows
+}
+
+func (q *SqlmockQuery) Return(out interface{}) Query {
+	rows := q.getRowsForOutType(out)
+	q.query = q.query.WillReturnRows(rows)
+
+	return q
+}
+
+type Exec interface {
+	Return(args ...interface{})
+}
+
+type Adapter interface {
+	Open() (error, *sql.DB, *DB, Asserter)
+	Close() error
+}
+
+type Asserter interface {
+	Query(query string) Query
+	// Exec(stmt string) Exec
+}
+
+type SqlmockAdapter struct {
+	mockDb *sql.DB
+	mock   *sqlmock.Sqlmock
+}
+
+// Open returns the raw sql.DB and a gorm DB instance
+func (adapter *SqlmockAdapter) Open() (error, *sql.DB, *DB, Asserter) {
+	mockDb, mock, err := sqlmock.NewWithDSN("mock_gorm_dsn")
+
+	if err != nil {
+		return err, nil, nil, nil
+	}
+
+	gormDb, err := Open("sqlmock", "mock_gorm_dsn")
+
+	if err != nil {
+		return err, nil, nil, nil
+	}
+
+	return nil, mockDb, gormDb, &SqlmockAsserter{mock: mock, sqlmockDB: mockDb}
+}
+
+func (adapter *SqlmockAdapter) Close() error {
+	return adapter.mockDb.Close()
+}
+
+type SqlmockAsserter struct {
+	sqlmockDB *sql.DB
+	mock      sqlmock.Sqlmock
+}
+
+func (a *SqlmockAsserter) Query(query string) Query {
+	q := a.mock.ExpectQuery(query)
+
+	return &SqlmockQuery{q}
+}
+
+// NewTestHelper returns a fresh TestHelper
+func NewTestHelper(adapter Adapter) (error, *DB, *TestHelper) {
+	err, mockDb, gormDb, asserter := adapter.Open()
+
+	if err != nil {
+		return err, nil, nil
+	}
+
+	return nil, gormDb, &TestHelper{gormDb: gormDb, mockDb: mockDb, asserter: asserter}
+}
diff --git a/gorm_expect_test.go b/gorm_expect_test.go
new file mode 100644
index 00000000..9e726c50
--- /dev/null
+++ b/gorm_expect_test.go
@@ -0,0 +1,26 @@
+package gorm_test
+
+import (
+	"testing"
+
+	"github.com/iantanwx/gorm"
+)
+
+func TestOpenWithSqlmock(t *testing.T) {
+	err, _, _ := gorm.NewTestHelper(&gorm.SqlmockAdapter{})
+
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func TestQuery(t *testing.T) {
+	err, db, helper := gorm.NewTestHelper(&gorm.SqlmockAdapter{})
+
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+
+	helper.ExpectFirst(&User{}).Return(&User{})
+	db.First(&User{})
+}