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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2014-2015 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package osutil_test
import (
"bytes"
"os"
"path/filepath"
"strings"
. "gopkg.in/check.v1"
"github.com/snapcore/snapd/osutil"
)
type CmpTestSuite struct{}
var _ = Suite(&CmpTestSuite{})
func (ts *CmpTestSuite) TestCmp(c *C) {
tmpdir := c.MkDir()
foo := filepath.Join(tmpdir, "foo")
f, err := os.Create(foo)
c.Assert(err, IsNil)
defer f.Close()
// test FilesAreEqual for various sizes:
// - bufsz not exceeded
// - bufsz matches file size
// - bufsz exceeds file size
canary := "1234567890123456"
for _, n := range []int{1, 128 / len(canary), (128 / len(canary)) + 1} {
for i := 0; i < n; i++ {
// Pick a smaller buffer size so that the test can complete quicker
c.Assert(osutil.FilesAreEqualChunked(foo, foo, 128), Equals, true)
_, err := f.WriteString(canary)
c.Assert(err, IsNil)
f.Sync()
}
}
}
func (ts *CmpTestSuite) TestCmpEmptyNeqMissing(c *C) {
tmpdir := c.MkDir()
foo := filepath.Join(tmpdir, "foo")
bar := filepath.Join(tmpdir, "bar")
f, err := os.Create(foo)
c.Assert(err, IsNil)
defer f.Close()
c.Assert(osutil.FilesAreEqual(foo, bar), Equals, false)
c.Assert(osutil.FilesAreEqual(bar, foo), Equals, false)
}
func (ts *CmpTestSuite) TestCmpEmptyNeqNonEmpty(c *C) {
tmpdir := c.MkDir()
foo := filepath.Join(tmpdir, "foo")
bar := filepath.Join(tmpdir, "bar")
f, err := os.Create(foo)
c.Assert(err, IsNil)
defer f.Close()
c.Assert(os.WriteFile(bar, []byte("x"), 0644), IsNil)
c.Assert(osutil.FilesAreEqual(foo, bar), Equals, false)
c.Assert(osutil.FilesAreEqual(bar, foo), Equals, false)
}
func (ts *CmpTestSuite) TestCmpStreams(c *C) {
for _, x := range []struct {
a string
b string
r bool
}{
{"hello", "hello", true},
{"hello", "world", false},
{"hello", "hell", false},
} {
c.Assert(osutil.StreamsEqual(strings.NewReader(x.a), strings.NewReader(x.b)), Equals, x.r)
}
}
func (s *CmpTestSuite) TestStreamsEqualChunked(c *C) {
text := "marry had a little lamb"
// Passing the same stream twice is not mishandled.
readerA := bytes.NewReader([]byte(text))
readerB := readerA
eq := osutil.StreamsEqualChunked(readerA, readerB, 0)
c.Check(eq, Equals, true)
// Passing two streams with the same content works as expected. Note that
// we are using different block sizes to check for additional edge cases.
for _, chunkSize := range []int{0, 1, len(text) / 2, len(text), len(text) + 1} {
readerA = bytes.NewReader([]byte(text))
readerB = bytes.NewReader([]byte(text))
eq := osutil.StreamsEqualChunked(readerA, readerB, chunkSize)
c.Check(eq, Equals, true, Commentf("chunk size %d", chunkSize))
}
// Passing two streams with unequal contents but equal length works as
// expected.
for _, chunkSize := range []int{0, 1, len(text) / 2, len(text), len(text) + 1} {
comment := Commentf("chunk size %d", chunkSize)
readerA = bytes.NewReader([]byte(strings.ToLower(text)))
readerB = bytes.NewReader([]byte(strings.ToUpper(text)))
eq = osutil.StreamsEqualChunked(readerA, readerB, chunkSize)
c.Check(eq, Equals, false, comment)
}
// Passing two streams which differer by tail only also works as expected.
for _, chunkSize := range []int{0, 1, len(text) / 2, len(text), len(text) + 1} {
textWithChangedTail := text[:len(text)-1] + strings.ToUpper(text[len(text)-1:])
c.Assert(textWithChangedTail, Not(Equals), text)
c.Assert(len(textWithChangedTail), Equals, len(text))
comment := Commentf("chunk size %d", chunkSize)
readerA = bytes.NewReader([]byte(text))
readerB = bytes.NewReader([]byte(textWithChangedTail))
eq = osutil.StreamsEqualChunked(readerA, readerB, chunkSize)
c.Check(eq, Equals, false, comment)
}
// Passing two streams with different length works as expected.
// Note that this is not used by EnsureDirState in practice.
for _, chunkSize := range []int{0, 1, len(text) / 2, len(text), len(text) + 1} {
comment := Commentf("A: %q, B: %q, chunk size %d", text, text[:len(text)/2], chunkSize)
readerA = bytes.NewReader([]byte(text))
readerB = bytes.NewReader([]byte(text[:len(text)/2]))
eq = osutil.StreamsEqualChunked(readerA, readerB, chunkSize)
c.Check(eq, Equals, false, comment)
// Readers passed the other way around.
readerA = bytes.NewReader([]byte(text))
readerB = bytes.NewReader([]byte(text[:len(text)/2]))
eq = osutil.StreamsEqualChunked(readerB, readerA, chunkSize)
c.Check(eq, Equals, false, comment)
}
}
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