Merge pull request #340 from DATA-DOG/feature/316

Add WithTXOption expectation to ExpectBegin

expectations.go

diff --git a/expectations.go b/expectations.go
index 8a6cd44..28d11ac 100644
--- a/expectations.go
+++ b/expectations.go
@@ -1,6 +1,7 @@
 package sqlmock
 
 import (
+	"database/sql"
 	"database/sql/driver"
 	"fmt"
 	"strings"
@@ -53,7 +54,8 @@
 // returned by *Sqlmock.ExpectBegin.
 type ExpectedBegin struct {
 	commonExpectation
-	delay time.Duration
+	delay  time.Duration
+	txOpts *driver.TxOptions
 }
 
 // WillReturnError allows to set an error for *sql.DB.Begin action
@@ -65,6 +67,9 @@
 // String returns string representation
 func (e *ExpectedBegin) String() string {
 	msg := "ExpectedBegin => expecting database transaction Begin"
+	if e.txOpts != nil {
+		msg += fmt.Sprintf(", with tx options: %+v", e.txOpts)
+	}
 	if e.err != nil {
 		msg += fmt.Sprintf(", which should return error: %s", e.err)
 	}
@@ -78,6 +83,15 @@
 	return e
 }
 
+// WithTxOptions allows to set transaction options for *sql.DB.Begin action
+func (e *ExpectedBegin) WithTxOptions(opts sql.TxOptions) *ExpectedBegin {
+	e.txOpts = &driver.TxOptions{
+		Isolation: driver.IsolationLevel(opts.Isolation),
+		ReadOnly:  opts.ReadOnly,
+	}
+	return e
+}
+
 // ExpectedCommit is used to manage *sql.Tx.Commit expectation
 // returned by *Sqlmock.ExpectCommit.
 type ExpectedCommit struct {

sqlmock.go

diff --git a/sqlmock.go b/sqlmock.go
index 3ee1256..a4f8f35 100644
--- a/sqlmock.go
+++ b/sqlmock.go
@@ -213,7 +213,7 @@
 
 // Begin meets http://golang.org/pkg/database/sql/driver/#Conn interface
 func (c *sqlmock) Begin() (driver.Tx, error) {
-	ex, err := c.begin()
+	ex, err := c.begin(driver.TxOptions{})
 	if ex != nil {
 		time.Sleep(ex.delay)
 	}
@@ -224,7 +224,7 @@
 	return c, nil
 }
 
-func (c *sqlmock) begin() (*ExpectedBegin, error) {
+func (c *sqlmock) begin(opts driver.TxOptions) (*ExpectedBegin, error) {
 	var expected *ExpectedBegin
 	var ok bool
 	var fulfilled int
@@ -252,9 +252,14 @@
 		}
 		return nil, fmt.Errorf(msg)
 	}
+	defer expected.Unlock()
+	if expected.txOpts != nil &&
+		expected.txOpts.Isolation != opts.Isolation &&
+		expected.txOpts.ReadOnly != opts.ReadOnly {
+		return nil, fmt.Errorf("expected transaction options do not match: %+v, got: %+v", expected.txOpts, opts)
+	}
 
 	expected.triggered = true
-	expected.Unlock()
 
 	return expected, expected.err
 }

sqlmock_go18.go

diff --git a/sqlmock_go18.go b/sqlmock_go18.go
index f268900..9644958 100644
--- a/sqlmock_go18.go
+++ b/sqlmock_go18.go
@@ -1,3 +1,4 @@
+//go:build go1.8
 // +build go1.8
 
 package sqlmock
@@ -66,7 +67,7 @@
 
 // Implement the "ConnBeginTx" interface
 func (c *sqlmock) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
-	ex, err := c.begin()
+	ex, err := c.begin(opts)
 	if ex != nil {
 		select {
 		case <-time.After(ex.delay):

sqlmock_go18_test.go

diff --git a/sqlmock_go18_test.go b/sqlmock_go18_test.go
index 6267f38..ddc7306 100644
--- a/sqlmock_go18_test.go
+++ b/sqlmock_go18_test.go
@@ -360,6 +360,66 @@
 	}
 }
 
+func TestContextBeginWithTxOptions(t *testing.T) {
+	t.Parallel()
+	db, mock, err := New()
+	if err != nil {
+		t.Errorf("an error '%s' was not expected when opening a stub database connection", err)
+	}
+	defer db.Close()
+
+	mock.ExpectBegin().WithTxOptions(sql.TxOptions{
+		Isolation: sql.LevelReadCommitted,
+		ReadOnly:  true,
+	})
+
+	ctx, cancel := context.WithCancel(context.Background())
+
+	go func() {
+		time.Sleep(time.Millisecond * 10)
+		cancel()
+	}()
+
+	_, err = db.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelReadCommitted, ReadOnly: false})
+	if err != nil {
+		t.Errorf("error was not expected, but got: %v", err)
+	}
+
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("there were unfulfilled expectations: %s", err)
+	}
+}
+
+func TestContextBeginWithTxOptionsMismatch(t *testing.T) {
+	t.Parallel()
+	db, mock, err := New()
+	if err != nil {
+		t.Errorf("an error '%s' was not expected when opening a stub database connection", err)
+	}
+	defer db.Close()
+
+	mock.ExpectBegin().WithTxOptions(sql.TxOptions{
+		Isolation: sql.LevelReadCommitted,
+		ReadOnly:  true,
+	})
+
+	ctx, cancel := context.WithCancel(context.Background())
+
+	go func() {
+		time.Sleep(time.Millisecond * 10)
+		cancel()
+	}()
+
+	_, err = db.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelDefault, ReadOnly: false})
+	if err == nil {
+		t.Error("error was expected, but there was none")
+	}
+
+	if err := mock.ExpectationsWereMet(); err == nil {
+		t.Errorf("was expecting an error, as the tx options did not match, but there wasn't one")
+	}
+}
+
 func TestContextPrepareCancel(t *testing.T) {
 	t.Parallel()
 	db, mock, err := New()