// Copyright 2020 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,
// See the License for the specific language governing permissions and
// limitations under the License.

package hash

import (
	"testing"

	"github.com/stretchr/testify/require"
)

func TestPositionInertia(t *testing.T) {
	t.Parallel()

	hash := NewPositionInertia()
	hash.Write([]byte("hello"), []byte("hash"))
	hash.Write([]byte("hello"), []byte("pingcap"))
	hash.Write([]byte("hello"), []byte("ticdc"))
	hash.Write([]byte("hello"), []byte("tools"))
	require.Equal(t, uint32(0x914505a7), hash.Sum32())

	hash.Reset()
	hash.Write([]byte("hello"), []byte("pingcap"))
	hash.Write([]byte("hello"), []byte("hash"))
	hash.Write([]byte("hello"), []byte("tools"))
	hash.Write([]byte("hello"), []byte("ticdc"))
	require.Equal(t, uint32(0x914505a7), hash.Sum32())

	hash.Reset()
	hash.Write([]byte("hello"), []byte("ticdc"))
	hash.Write([]byte("hello"), []byte("hash"))
	hash.Write([]byte("hello"), []byte("tools"))
	hash.Write([]byte("hello"), []byte("pingcap"))
	require.Equal(t, uint32(0x914505a7), hash.Sum32())

	hash.Reset()
	hash.Write([]byte("ticdc"), []byte("hello"))
	hash.Write([]byte("hello"), []byte("hash"))
	hash.Write([]byte("hello"), []byte("tools"))
	hash.Write([]byte("hello"), []byte("pingcap"))
	require.Equal(t, uint32(0xf21b4f40), hash.Sum32())

	hash.Reset()
	hash.Write([]byte("ticdc"), []byte("hello"))
	hash.Write([]byte("hello"), []byte("hash"))
	hash.Write([]byte("tools"), []byte("hello"))
	hash.Write([]byte("hello"), []byte("pingcap"))
	require.Equal(t, uint32(0x7cd6194a), hash.Sum32())
}