// Copyright 2021 The Prometheus Authors
// 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.

package storage

import (
	"testing"

	"github.com/stretchr/testify/require"

	"github.com/prometheus/prometheus/tsdb/chunkenc"
)

func TestListSeriesIterator(t *testing.T) {
	it := NewListSeriesIterator(samples{
		sample{0, 0, nil, nil},
		sample{1, 1, nil, nil},
		sample{1, 1.5, nil, nil},
		sample{2, 2, nil, nil},
		sample{3, 3, nil, nil},
	})

	// Seek to the first sample with ts=1.
	require.Equal(t, chunkenc.ValFloat, it.Seek(1))
	ts, v := it.At()
	require.Equal(t, int64(1), ts)
	require.Equal(t, 1., v)

	// Seek one further, next sample still has ts=1.
	require.Equal(t, chunkenc.ValFloat, it.Next())
	ts, v = it.At()
	require.Equal(t, int64(1), ts)
	require.Equal(t, 1.5, v)

	// Seek again to 1 and make sure we stay where we are.
	require.Equal(t, chunkenc.ValFloat, it.Seek(1))
	ts, v = it.At()
	require.Equal(t, int64(1), ts)
	require.Equal(t, 1.5, v)

	// Another seek.
	require.Equal(t, chunkenc.ValFloat, it.Seek(3))
	ts, v = it.At()
	require.Equal(t, int64(3), ts)
	require.Equal(t, 3., v)

	// And we don't go back.
	require.Equal(t, chunkenc.ValFloat, it.Seek(2))
	ts, v = it.At()
	require.Equal(t, int64(3), ts)
	require.Equal(t, 3., v)

	// Seek beyond the end.
	require.Equal(t, chunkenc.ValNone, it.Seek(5))
	// And we don't go back. (This exposes issue #10027.)
	require.Equal(t, chunkenc.ValNone, it.Seek(2))
}