externaltoc_test.go

Documentation: github.com/containerd/stargz-snapshotter/estargz/externaltoc

     1  /*
     2     Copyright The containerd Authors.
     3  
     4     Licensed under the Apache License, Version 2.0 (the "License");
     5     you may not use this file except in compliance with the License.
     6     You may obtain a copy of the License at
     7  
     8         http://www.apache.org/licenses/LICENSE-2.0
     9  
    10     Unless required by applicable law or agreed to in writing, software
    11     distributed under the License is distributed on an "AS IS" BASIS,
    12     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13     See the License for the specific language governing permissions and
    14     limitations under the License.
    15  */
    16  
    17  package externaltoc
    18  
    19  import (
    20  	"bytes"
    21  	"compress/gzip"
    22  	"fmt"
    23  	"testing"
    24  
    25  	"github.com/containerd/stargz-snapshotter/estargz"
    26  )
    27  
    28  // TestGzipEStargz tests gzip-based external TOC eStargz
    29  func TestGzipEStargz(t *testing.T) {
    30  	estargz.CompressionTestSuite(t,
    31  		gzipControllerWithLevel(gzip.NoCompression),
    32  		gzipControllerWithLevel(gzip.BestSpeed),
    33  		gzipControllerWithLevel(gzip.BestCompression),
    34  		gzipControllerWithLevel(gzip.DefaultCompression),
    35  		gzipControllerWithLevel(gzip.HuffmanOnly),
    36  	)
    37  }
    38  
    39  func gzipControllerWithLevel(compressionLevel int) estargz.TestingControllerFactory {
    40  	return func() estargz.TestingController {
    41  		compressor := NewGzipCompressorWithLevel(compressionLevel)
    42  		decompressor := NewGzipDecompressor(func() ([]byte, error) {
    43  			buf := new(bytes.Buffer)
    44  			if _, err := compressor.WriteTOCTo(buf); err != nil {
    45  				return nil, err
    46  			}
    47  			return buf.Bytes(), nil
    48  		})
    49  		return &gzipController{compressor, decompressor}
    50  	}
    51  }
    52  
    53  type gzipController struct {
    54  	*GzipCompressor
    55  	*GzipDecompressor
    56  }
    57  
    58  func (gc *gzipController) String() string {
    59  	return fmt.Sprintf("externaltoc_gzip_compression_level=%v", gc.GzipCompressor.compressionLevel)
    60  }
    61  
    62  // TestStream tests the passed estargz blob contains the specified list of streams.
    63  func (gc *gzipController) TestStreams(t *testing.T, b []byte, streams []int64) {
    64  	estargz.CheckGzipHasStreams(t, b, streams)
    65  }
    66  
    67  func (gc *gzipController) DiffIDOf(t *testing.T, b []byte) string {
    68  	return estargz.GzipDiffIDOf(t, b)
    69  }
    70  
    71  // Tests footer encoding, size, and parsing of gzip-based eStargz.
    72  func TestGzipFooter(t *testing.T) {
    73  	footer, err := gzipFooterBytes()
    74  	if err != nil {
    75  		t.Fatalf("failed gzipFooterBytes: %v", err)
    76  	}
    77  	if len(footer) != FooterSize {
    78  		t.Fatalf("footer length was %d, not expected %d. got bytes: %q", len(footer), FooterSize, footer)
    79  	}
    80  	_, gotTOCOffset, _, err := (&GzipDecompressor{}).ParseFooter(footer)
    81  	if err != nil {
    82  		t.Fatalf("failed to parse footer, footer: %x: err: %v", footer, err)
    83  	}
    84  	if gotTOCOffset != -1 {
    85  		t.Fatalf("ParseFooter(footerBytes) must return -1 for external toc but got %d", gotTOCOffset)
    86  	}
    87  }
    88
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