From 4ee8b12ce2ef76af35fe83315aba49504278eb62 Mon Sep 17 00:00:00 2001
From: Charlie Tonneslan <cst0520@gmail.com>
Date: Fri, 29 May 2026 08:29:04 -0400
Subject: [PATCH] fix: ExpectBegin TxOptions check uses && instead of ||
 (closes #342)

The Begin path required both Isolation AND ReadOnly to differ before
the "options do not match" error fired, so any single-field mismatch
silently passed. The existing TestContextBeginWithTxOptions even
depended on that buggy behavior (Isolation matched, ReadOnly didn't,
expectation still considered fulfilled).

Switched the conjunction to a disjunction and fixed the existing test
to use matching options. Added two new mismatch tests (one for
Isolation-only differs, one for ReadOnly-only differs) that fail on
master and pass with the fix.

Signed-off-by: Charlie Tonneslan <cst0520@gmail.com>
---
 sqlmock.go           |  4 ++--
 sqlmock_go18_test.go | 48 +++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/sqlmock.go b/sqlmock.go
index a4f8f35..6380491 100644
--- a/sqlmock.go
+++ b/sqlmock.go
@@ -254,8 +254,8 @@ func (c *sqlmock) begin(opts driver.TxOptions) (*ExpectedBegin, error) {
 	}
 	defer expected.Unlock()
 	if expected.txOpts != nil &&
-		expected.txOpts.Isolation != opts.Isolation &&
-		expected.txOpts.ReadOnly != opts.ReadOnly {
+		(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)
 	}
 
diff --git a/sqlmock_go18_test.go b/sqlmock_go18_test.go
index ddc7306..d95a8b9 100644
--- a/sqlmock_go18_test.go
+++ b/sqlmock_go18_test.go
@@ -380,7 +380,7 @@ func TestContextBeginWithTxOptions(t *testing.T) {
 		cancel()
 	}()
 
-	_, err = db.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelReadCommitted, ReadOnly: false})
+	_, err = db.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelReadCommitted, ReadOnly: true})
 	if err != nil {
 		t.Errorf("error was not expected, but got: %v", err)
 	}
@@ -420,6 +420,52 @@ func TestContextBeginWithTxOptionsMismatch(t *testing.T) {
 	}
 }
 
+func TestContextBeginWithTxOptionsReadOnlyMismatch(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())
+	defer cancel()
+
+	// Isolation matches, but ReadOnly does not. Should still error.
+	_, err = db.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelReadCommitted, ReadOnly: false})
+	if err == nil {
+		t.Error("error was expected on ReadOnly mismatch, but there was none")
+	}
+}
+
+func TestContextBeginWithTxOptionsIsolationMismatch(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())
+	defer cancel()
+
+	// ReadOnly matches, but Isolation does not. Should still error.
+	_, err = db.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelSerializable, ReadOnly: true})
+	if err == nil {
+		t.Error("error was expected on Isolation mismatch, but there was none")
+	}
+}
+
 func TestContextPrepareCancel(t *testing.T) {
 	t.Parallel()
 	db, mock, err := New()