github.com/cockroachdb/pebble@v0.0.0-20231214172447-ab4952c5f87b/sstable/compression_test.go (about)

     1  // Copyright 2023 The LevelDB-Go and Pebble Authors. All rights reserved. Use
     2  // of this source code is governed by a BSD-style license that can be found in
     3  // the LICENSE file.
     4  
     5  package sstable
     6  
     7  import (
     8  	"encoding/binary"
     9  	"math/rand"
    10  	"testing"
    11  	"time"
    12  
    13  	"github.com/cockroachdb/pebble/internal/cache"
    14  	"github.com/stretchr/testify/require"
    15  )
    16  
    17  func TestCompressionRoundtrip(t *testing.T) {
    18  	seed := time.Now().UnixNano()
    19  	t.Logf("seed %d", seed)
    20  	rng := rand.New(rand.NewSource(seed))
    21  
    22  	for compression := DefaultCompression + 1; compression < NCompression; compression++ {
    23  		t.Run(compression.String(), func(t *testing.T) {
    24  			payload := make([]byte, rng.Intn(10<<10 /* 10 KiB */))
    25  			rng.Read(payload)
    26  			// Create a randomly-sized buffer to house the compressed output. If it's
    27  			// not sufficient, compressBlock should allocate one that is.
    28  			compressedBuf := make([]byte, rng.Intn(1<<10 /* 1 KiB */))
    29  
    30  			btyp, compressed := compressBlock(compression, payload, compressedBuf)
    31  			v, err := decompressBlock(btyp, compressed)
    32  			require.NoError(t, err)
    33  			got := payload
    34  			if v != nil {
    35  				got = v.Buf()
    36  				require.Equal(t, payload, got)
    37  				cache.Free(v)
    38  			}
    39  		})
    40  	}
    41  }
    42  
    43  // TestDecompressionError tests that a decompressing a value that does not
    44  // decompress returns an error.
    45  func TestDecompressionError(t *testing.T) {
    46  	rng := rand.New(rand.NewSource(1 /* fixed seed */))
    47  
    48  	// Create a buffer to represent a faux zstd compressed block. It's prefixed
    49  	// with a uvarint of the appropriate length, followed by garabge.
    50  	fauxCompressed := make([]byte, rng.Intn(10<<10 /* 10 KiB */))
    51  	compressedPayloadLen := len(fauxCompressed) - binary.MaxVarintLen64
    52  	n := binary.PutUvarint(fauxCompressed, uint64(compressedPayloadLen))
    53  	fauxCompressed = fauxCompressed[:n+compressedPayloadLen]
    54  	rng.Read(fauxCompressed[n:])
    55  
    56  	v, err := decompressBlock(zstdCompressionBlockType, fauxCompressed)
    57  	t.Log(err)
    58  	require.Error(t, err)
    59  	require.Nil(t, v)
    60  }