// Copyright 2025 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//go:build nextgen

package variable

import (
	"testing"

	"github.com/pingcap/tidb/pkg/sessionctx/vardef"
	"github.com/stretchr/testify/require"
)

func TestTiDBPessimisticTransactionFairLocking(t *testing.T) {
	sv := GetSysVar(vardef.TiDBPessimisticTransactionFairLocking)
	vars := NewSessionVars(nil)

	val, err := sv.Validate(vars, "off", vardef.ScopeSession)
	require.NoError(t, err)
	require.Equal(t, vardef.Off, val)
	require.Nil(t, sv.SetSessionFromHook(vars, val))
	require.False(t, vars.PessimisticTransactionFairLocking)

	val, err = sv.Validate(vars, "on", vardef.ScopeSession)
	require.Error(t, err)
	require.True(t, ErrNotSupportedInNextGen.Equal(err))
	require.Equal(t, vardef.Off, val)
	require.Nil(t, sv.SetSessionFromHook(vars, val))
	require.False(t, vars.PessimisticTransactionFairLocking)

	val = GlobalSystemVariableInitialValue(vardef.TiDBPessimisticTransactionFairLocking, BoolToOnOff(vardef.DefTiDBPessimisticTransactionFairLocking))
	require.Equal(t, vardef.Off, val)
}