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[bytom/vapor.git] / vendor / github.com / syndtr / goleveldb / leveldb / util / buffer_test.go
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/util/buffer_test.go b/vendor/github.com/syndtr/goleveldb/leveldb/util/buffer_test.go
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+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package util
+
+import (
+       "bytes"
+       "io"
+       "math/rand"
+       "runtime"
+       "testing"
+)
+
+const N = 10000      // make this bigger for a larger (and slower) test
+var data string      // test data for write tests
+var testBytes []byte // test data; same as data but as a slice.
+
+func init() {
+       testBytes = make([]byte, N)
+       for i := 0; i < N; i++ {
+               testBytes[i] = 'a' + byte(i%26)
+       }
+       data = string(testBytes)
+}
+
+// Verify that contents of buf match the string s.
+func check(t *testing.T, testname string, buf *Buffer, s string) {
+       bytes := buf.Bytes()
+       str := buf.String()
+       if buf.Len() != len(bytes) {
+               t.Errorf("%s: buf.Len() == %d, len(buf.Bytes()) == %d", testname, buf.Len(), len(bytes))
+       }
+
+       if buf.Len() != len(str) {
+               t.Errorf("%s: buf.Len() == %d, len(buf.String()) == %d", testname, buf.Len(), len(str))
+       }
+
+       if buf.Len() != len(s) {
+               t.Errorf("%s: buf.Len() == %d, len(s) == %d", testname, buf.Len(), len(s))
+       }
+
+       if string(bytes) != s {
+               t.Errorf("%s: string(buf.Bytes()) == %q, s == %q", testname, string(bytes), s)
+       }
+}
+
+// Fill buf through n writes of byte slice fub.
+// The initial contents of buf corresponds to the string s;
+// the result is the final contents of buf returned as a string.
+func fillBytes(t *testing.T, testname string, buf *Buffer, s string, n int, fub []byte) string {
+       check(t, testname+" (fill 1)", buf, s)
+       for ; n > 0; n-- {
+               m, err := buf.Write(fub)
+               if m != len(fub) {
+                       t.Errorf(testname+" (fill 2): m == %d, expected %d", m, len(fub))
+               }
+               if err != nil {
+                       t.Errorf(testname+" (fill 3): err should always be nil, found err == %s", err)
+               }
+               s += string(fub)
+               check(t, testname+" (fill 4)", buf, s)
+       }
+       return s
+}
+
+func TestNewBuffer(t *testing.T) {
+       buf := NewBuffer(testBytes)
+       check(t, "NewBuffer", buf, data)
+}
+
+// Empty buf through repeated reads into fub.
+// The initial contents of buf corresponds to the string s.
+func empty(t *testing.T, testname string, buf *Buffer, s string, fub []byte) {
+       check(t, testname+" (empty 1)", buf, s)
+
+       for {
+               n, err := buf.Read(fub)
+               if n == 0 {
+                       break
+               }
+               if err != nil {
+                       t.Errorf(testname+" (empty 2): err should always be nil, found err == %s", err)
+               }
+               s = s[n:]
+               check(t, testname+" (empty 3)", buf, s)
+       }
+
+       check(t, testname+" (empty 4)", buf, "")
+}
+
+func TestBasicOperations(t *testing.T) {
+       var buf Buffer
+
+       for i := 0; i < 5; i++ {
+               check(t, "TestBasicOperations (1)", &buf, "")
+
+               buf.Reset()
+               check(t, "TestBasicOperations (2)", &buf, "")
+
+               buf.Truncate(0)
+               check(t, "TestBasicOperations (3)", &buf, "")
+
+               n, err := buf.Write([]byte(data[0:1]))
+               if n != 1 {
+                       t.Errorf("wrote 1 byte, but n == %d", n)
+               }
+               if err != nil {
+                       t.Errorf("err should always be nil, but err == %s", err)
+               }
+               check(t, "TestBasicOperations (4)", &buf, "a")
+
+               buf.WriteByte(data[1])
+               check(t, "TestBasicOperations (5)", &buf, "ab")
+
+               n, err = buf.Write([]byte(data[2:26]))
+               if n != 24 {
+                       t.Errorf("wrote 25 bytes, but n == %d", n)
+               }
+               check(t, "TestBasicOperations (6)", &buf, string(data[0:26]))
+
+               buf.Truncate(26)
+               check(t, "TestBasicOperations (7)", &buf, string(data[0:26]))
+
+               buf.Truncate(20)
+               check(t, "TestBasicOperations (8)", &buf, string(data[0:20]))
+
+               empty(t, "TestBasicOperations (9)", &buf, string(data[0:20]), make([]byte, 5))
+               empty(t, "TestBasicOperations (10)", &buf, "", make([]byte, 100))
+
+               buf.WriteByte(data[1])
+               c, err := buf.ReadByte()
+               if err != nil {
+                       t.Error("ReadByte unexpected eof")
+               }
+               if c != data[1] {
+                       t.Errorf("ReadByte wrong value c=%v", c)
+               }
+               c, err = buf.ReadByte()
+               if err == nil {
+                       t.Error("ReadByte unexpected not eof")
+               }
+       }
+}
+
+func TestLargeByteWrites(t *testing.T) {
+       var buf Buffer
+       limit := 30
+       if testing.Short() {
+               limit = 9
+       }
+       for i := 3; i < limit; i += 3 {
+               s := fillBytes(t, "TestLargeWrites (1)", &buf, "", 5, testBytes)
+               empty(t, "TestLargeByteWrites (2)", &buf, s, make([]byte, len(data)/i))
+       }
+       check(t, "TestLargeByteWrites (3)", &buf, "")
+}
+
+func TestLargeByteReads(t *testing.T) {
+       var buf Buffer
+       for i := 3; i < 30; i += 3 {
+               s := fillBytes(t, "TestLargeReads (1)", &buf, "", 5, testBytes[0:len(testBytes)/i])
+               empty(t, "TestLargeReads (2)", &buf, s, make([]byte, len(data)))
+       }
+       check(t, "TestLargeByteReads (3)", &buf, "")
+}
+
+func TestMixedReadsAndWrites(t *testing.T) {
+       var buf Buffer
+       s := ""
+       for i := 0; i < 50; i++ {
+               wlen := rand.Intn(len(data))
+               s = fillBytes(t, "TestMixedReadsAndWrites (1)", &buf, s, 1, testBytes[0:wlen])
+               rlen := rand.Intn(len(data))
+               fub := make([]byte, rlen)
+               n, _ := buf.Read(fub)
+               s = s[n:]
+       }
+       empty(t, "TestMixedReadsAndWrites (2)", &buf, s, make([]byte, buf.Len()))
+}
+
+func TestNil(t *testing.T) {
+       var b *Buffer
+       if b.String() != "<nil>" {
+               t.Errorf("expected <nil>; got %q", b.String())
+       }
+}
+
+func TestReadFrom(t *testing.T) {
+       var buf Buffer
+       for i := 3; i < 30; i += 3 {
+               s := fillBytes(t, "TestReadFrom (1)", &buf, "", 5, testBytes[0:len(testBytes)/i])
+               var b Buffer
+               b.ReadFrom(&buf)
+               empty(t, "TestReadFrom (2)", &b, s, make([]byte, len(data)))
+       }
+}
+
+func TestWriteTo(t *testing.T) {
+       var buf Buffer
+       for i := 3; i < 30; i += 3 {
+               s := fillBytes(t, "TestWriteTo (1)", &buf, "", 5, testBytes[0:len(testBytes)/i])
+               var b Buffer
+               buf.WriteTo(&b)
+               empty(t, "TestWriteTo (2)", &b, s, make([]byte, len(data)))
+       }
+}
+
+func TestNext(t *testing.T) {
+       b := []byte{0, 1, 2, 3, 4}
+       tmp := make([]byte, 5)
+       for i := 0; i <= 5; i++ {
+               for j := i; j <= 5; j++ {
+                       for k := 0; k <= 6; k++ {
+                               // 0 <= i <= j <= 5; 0 <= k <= 6
+                               // Check that if we start with a buffer
+                               // of length j at offset i and ask for
+                               // Next(k), we get the right bytes.
+                               buf := NewBuffer(b[0:j])
+                               n, _ := buf.Read(tmp[0:i])
+                               if n != i {
+                                       t.Fatalf("Read %d returned %d", i, n)
+                               }
+                               bb := buf.Next(k)
+                               want := k
+                               if want > j-i {
+                                       want = j - i
+                               }
+                               if len(bb) != want {
+                                       t.Fatalf("in %d,%d: len(Next(%d)) == %d", i, j, k, len(bb))
+                               }
+                               for l, v := range bb {
+                                       if v != byte(l+i) {
+                                               t.Fatalf("in %d,%d: Next(%d)[%d] = %d, want %d", i, j, k, l, v, l+i)
+                                       }
+                               }
+                       }
+               }
+       }
+}
+
+var readBytesTests = []struct {
+       buffer   string
+       delim    byte
+       expected []string
+       err      error
+}{
+       {"", 0, []string{""}, io.EOF},
+       {"a\x00", 0, []string{"a\x00"}, nil},
+       {"abbbaaaba", 'b', []string{"ab", "b", "b", "aaab"}, nil},
+       {"hello\x01world", 1, []string{"hello\x01"}, nil},
+       {"foo\nbar", 0, []string{"foo\nbar"}, io.EOF},
+       {"alpha\nbeta\ngamma\n", '\n', []string{"alpha\n", "beta\n", "gamma\n"}, nil},
+       {"alpha\nbeta\ngamma", '\n', []string{"alpha\n", "beta\n", "gamma"}, io.EOF},
+}
+
+func TestReadBytes(t *testing.T) {
+       for _, test := range readBytesTests {
+               buf := NewBuffer([]byte(test.buffer))
+               var err error
+               for _, expected := range test.expected {
+                       var bytes []byte
+                       bytes, err = buf.ReadBytes(test.delim)
+                       if string(bytes) != expected {
+                               t.Errorf("expected %q, got %q", expected, bytes)
+                       }
+                       if err != nil {
+                               break
+                       }
+               }
+               if err != test.err {
+                       t.Errorf("expected error %v, got %v", test.err, err)
+               }
+       }
+}
+
+func TestGrow(t *testing.T) {
+       x := []byte{'x'}
+       y := []byte{'y'}
+       tmp := make([]byte, 72)
+       for _, startLen := range []int{0, 100, 1000, 10000, 100000} {
+               xBytes := bytes.Repeat(x, startLen)
+               for _, growLen := range []int{0, 100, 1000, 10000, 100000} {
+                       buf := NewBuffer(xBytes)
+                       // If we read, this affects buf.off, which is good to test.
+                       readBytes, _ := buf.Read(tmp)
+                       buf.Grow(growLen)
+                       yBytes := bytes.Repeat(y, growLen)
+                       // Check no allocation occurs in write, as long as we're single-threaded.
+                       var m1, m2 runtime.MemStats
+                       runtime.ReadMemStats(&m1)
+                       buf.Write(yBytes)
+                       runtime.ReadMemStats(&m2)
+                       if runtime.GOMAXPROCS(-1) == 1 && m1.Mallocs != m2.Mallocs {
+                               t.Errorf("allocation occurred during write")
+                       }
+                       // Check that buffer has correct data.
+                       if !bytes.Equal(buf.Bytes()[0:startLen-readBytes], xBytes[readBytes:]) {
+                               t.Errorf("bad initial data at %d %d", startLen, growLen)
+                       }
+                       if !bytes.Equal(buf.Bytes()[startLen-readBytes:startLen-readBytes+growLen], yBytes) {
+                               t.Errorf("bad written data at %d %d", startLen, growLen)
+                       }
+               }
+       }
+}
+
+// Was a bug: used to give EOF reading empty slice at EOF.
+func TestReadEmptyAtEOF(t *testing.T) {
+       b := new(Buffer)
+       slice := make([]byte, 0)
+       n, err := b.Read(slice)
+       if err != nil {
+               t.Errorf("read error: %v", err)
+       }
+       if n != 0 {
+               t.Errorf("wrong count; got %d want 0", n)
+       }
+}
+
+// Tests that we occasionally compact. Issue 5154.
+func TestBufferGrowth(t *testing.T) {
+       var b Buffer
+       buf := make([]byte, 1024)
+       b.Write(buf[0:1])
+       var cap0 int
+       for i := 0; i < 5<<10; i++ {
+               b.Write(buf)
+               b.Read(buf)
+               if i == 0 {
+                       cap0 = cap(b.buf)
+               }
+       }
+       cap1 := cap(b.buf)
+       // (*Buffer).grow allows for 2x capacity slop before sliding,
+       // so set our error threshold at 3x.
+       if cap1 > cap0*3 {
+               t.Errorf("buffer cap = %d; too big (grew from %d)", cap1, cap0)
+       }
+}
+
+// From Issue 5154.
+func BenchmarkBufferNotEmptyWriteRead(b *testing.B) {
+       buf := make([]byte, 1024)
+       for i := 0; i < b.N; i++ {
+               var b Buffer
+               b.Write(buf[0:1])
+               for i := 0; i < 5<<10; i++ {
+                       b.Write(buf)
+                       b.Read(buf)
+               }
+       }
+}
+
+// Check that we don't compact too often. From Issue 5154.
+func BenchmarkBufferFullSmallReads(b *testing.B) {
+       buf := make([]byte, 1024)
+       for i := 0; i < b.N; i++ {
+               var b Buffer
+               b.Write(buf)
+               for b.Len()+20 < cap(b.buf) {
+                       b.Write(buf[:10])
+               }
+               for i := 0; i < 5<<10; i++ {
+                       b.Read(buf[:1])
+                       b.Write(buf[:1])
+               }
+       }
+}