Sql driver mock for Golang

This is a mock driver as database/sql/driver which is very flexible and pragmatic to manage and mock expected queries. All the expectations should be met and all queries and actions triggered should be mocked in order to pass a test. The package has no 3rd party dependencies.

NOTE: regarding major issues #20 and #9 the api has changed to support concurrency and more than one database connection.

If you need an old version, checkout go-sqlmock at gopkg.in:

go get gopkg.in/DATA-DOG/go-sqlmock.v0

Otherwise use the v1 branch from master which should be stable afterwards, because all the issues which were known will be fixed in this version.

Install

go get gopkg.in/DATA-DOG/go-sqlmock.v1

Or take an older version:

go get gopkg.in/DATA-DOG/go-sqlmock.v0

Documentation and Examples

Visit godoc for general examples and public api reference. See .travis.yml for supported go versions. Different use case, is to functionally test with a real database - go-txdb all database related actions are isolated within a single transaction so the database can remain in the same state.

See implementation examples:

• blog API server
• the same orders example

Something you may want to test

package main

import "database/sql"

func recordStats(db *sql.DB, userID, productID int64) (err error) {
	tx, err := db.Begin()
	if err != nil {
		return
	}

	defer func() {
		switch err {
		case nil:
			err = tx.Commit()
		default:
			tx.Rollback()
		}
	}()

	if _, err = tx.Exec("UPDATE products SET views = views + 1"); err != nil {
		return
	}
	if _, err = tx.Exec("INSERT INTO product_viewers (user_id, product_id) VALUES (?, ?)", userID, productID); err != nil {
		return
	}
	return
}

func main() {
	// @NOTE: the real connection is not required for tests
	db, err := sql.Open("mysql", "root@/blog")
	if err != nil {
		panic(err)
	}
	defer db.Close()

	if err = recordStats(db, 1 /*some user id*/, 5 /*some product id*/); err != nil {
		panic(err)
	}
}

Tests with sqlmock

package main

import (
	"fmt"
	"testing"

	"github.com/DATA-DOG/go-sqlmock"
)

// a successful case
func TestShouldUpdateStats(t *testing.T) {
	db, mock, err := sqlmock.New()
	if err != nil {
		t.Fatalf("an error '%s' was not expected when opening a stub database connection", err)
	}
	defer db.Close()

	mock.ExpectBegin()
	mock.ExpectExec("UPDATE products").WillReturnResult(sqlmock.NewResult(1, 1))
	mock.ExpectExec("INSERT INTO product_viewers").WithArgs(2, 3).WillReturnResult(sqlmock.NewResult(1, 1))
	mock.ExpectCommit()

	// now we execute our method
	if err = recordStats(db, 2, 3); err != nil {
		t.Errorf("error was not expected while updating stats: %s", err)
	}

	// we make sure that all expectations were met
	if err := mock.ExpectationsWereMet(); err != nil {
		t.Errorf("there were unfulfilled expections: %s", err)
	}
}

// a failing test case
func TestShouldRollbackStatUpdatesOnFailure(t *testing.T) {
	db, mock, err := sqlmock.New()
	if err != nil {
		t.Fatalf("an error '%s' was not expected when opening a stub database connection", err)
	}
	defer db.Close()

	mock.ExpectBegin()
	mock.ExpectExec("UPDATE products").WillReturnResult(sqlmock.NewResult(1, 1))
	mock.ExpectExec("INSERT INTO product_viewers").
		WithArgs(2, 3).
		WillReturnError(fmt.Errorf("some error"))
	mock.ExpectRollback()

	// now we execute our method
	if err = recordStats(db, 2, 3); err == nil {
		t.Errorf("was expecting an error, but there was none")
	}

	// we make sure that all expectations were met
	if err := mock.ExpectationsWereMet(); err != nil {
		t.Errorf("there were unfulfilled expections: %s", err)
	}
}

Run tests

go test -race

Changes

• 2015-08-27 - v1 api change, concurrency support, all known issues fixed.
• 2014-08-16 instead of panic during reflect type mismatch when comparing query arguments - now return error
• 2014-08-14 added sqlmock.NewErrorResult which gives an option to return driver.Result with errors for interface methods, see issue
• 2014-05-29 allow to match arguments in more sophisticated ways, by providing an sqlmock.Argument interface
• 2014-04-21 introduce sqlmock.New() to open a mock database connection for tests. This method calls sql.DB.Ping to ensure that connection is open, see issue. This way on Close it will surely assert if all expectations are met, even if database was not triggered at all. The old way is still available, but it is advisable to call db.Ping manually before asserting with db.Close.
• 2014-02-14 RowsFromCSVString is now a part of Rows interface named as FromCSVString. It has changed to allow more ways to construct rows and to easily extend this API in future. See issue 1 RowsFromCSVString is deprecated and will be removed in future

Contributions

Feel free to open a pull request. Note, if you wish to contribute an extension to public (exported methods or types) - please open an issue before, to discuss whether these changes can be accepted. All backward incompatible changes are and will be treated cautiously

License

The three clause BSD license