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// Copyright 2011 Google Inc. All rights reserved.
// Use of this source code is governed by the Apache 2.0
// license that can be found in the LICENSE file.
package blobstore
import (
"io"
"os"
"strconv"
"strings"
"testing"
"google.golang.org/appengine"
"google.golang.org/appengine/internal/aetesting"
pb "google.golang.org/appengine/internal/blobstore"
)
const rbs = readBufferSize
func min(x, y int) int {
if x < y {
return x
}
return y
}
func fakeFetchData(req *pb.FetchDataRequest, res *pb.FetchDataResponse) error {
i0 := int(*req.StartIndex)
i1 := int(*req.EndIndex + 1) // Blobstore's end-indices are inclusive; Go's are exclusive.
bk := *req.BlobKey
if i := strings.Index(bk, "."); i != -1 {
// Strip everything past the ".".
bk = bk[:i]
}
switch bk {
case "a14p":
const s = "abcdefghijklmnop"
i0 := min(len(s), i0)
i1 := min(len(s), i1)
res.Data = []byte(s[i0:i1])
case "longBlob":
res.Data = make([]byte, i1-i0)
for i := range res.Data {
res.Data[i] = 'A' + uint8(i0/rbs)
i0++
}
}
return nil
}
// step is one step of a readerTest.
// It consists of a Reader method to call, the method arguments
// (lenp, offset, whence) and the expected results.
type step struct {
method string
lenp int
offset int64
whence int
want string
wantErr error
}
var readerTest = []struct {
blobKey string
step []step
}{
{"noSuchBlobKey", []step{
{"Read", 8, 0, 0, "", io.EOF},
}},
{"a14p.0", []step{
// Test basic reads.
{"Read", 1, 0, 0, "a", nil},
{"Read", 3, 0, 0, "bcd", nil},
{"Read", 1, 0, 0, "e", nil},
{"Read", 2, 0, 0, "fg", nil},
// Test Seek.
{"Seek", 0, 2, os.SEEK_SET, "2", nil},
{"Read", 5, 0, 0, "cdefg", nil},
{"Seek", 0, 2, os.SEEK_CUR, "9", nil},
{"Read", 1, 0, 0, "j", nil},
// Test reads up to and past EOF.
{"Read", 5, 0, 0, "klmno", nil},
{"Read", 5, 0, 0, "p", nil},
{"Read", 5, 0, 0, "", io.EOF},
// Test ReadAt.
{"ReadAt", 4, 0, 0, "abcd", nil},
{"ReadAt", 4, 3, 0, "defg", nil},
{"ReadAt", 4, 12, 0, "mnop", nil},
{"ReadAt", 4, 13, 0, "nop", io.EOF},
{"ReadAt", 4, 99, 0, "", io.EOF},
}},
{"a14p.1", []step{
// Test Seek before any reads.
{"Seek", 0, 2, os.SEEK_SET, "2", nil},
{"Read", 1, 0, 0, "c", nil},
// Test that ReadAt doesn't affect the Read offset.
{"ReadAt", 3, 9, 0, "jkl", nil},
{"Read", 3, 0, 0, "def", nil},
}},
{"a14p.2", []step{
// Test ReadAt before any reads or seeks.
{"ReadAt", 2, 14, 0, "op", nil},
}},
{"longBlob.0", []step{
// Test basic read.
{"Read", 1, 0, 0, "A", nil},
// Test that Read returns early when the buffer is exhausted.
{"Seek", 0, rbs - 2, os.SEEK_SET, strconv.Itoa(rbs - 2), nil},
{"Read", 5, 0, 0, "AA", nil},
{"Read", 3, 0, 0, "BBB", nil},
// Test that what we just read is still in the buffer.
{"Seek", 0, rbs - 2, os.SEEK_SET, strconv.Itoa(rbs - 2), nil},
{"Read", 5, 0, 0, "AABBB", nil},
// Test ReadAt.
{"ReadAt", 3, rbs - 4, 0, "AAA", nil},
{"ReadAt", 6, rbs - 4, 0, "AAAABB", nil},
{"ReadAt", 8, rbs - 4, 0, "AAAABBBB", nil},
{"ReadAt", 5, rbs - 4, 0, "AAAAB", nil},
{"ReadAt", 2, rbs - 4, 0, "AA", nil},
// Test seeking backwards from the Read offset.
{"Seek", 0, 2*rbs - 8, os.SEEK_SET, strconv.Itoa(2*rbs - 8), nil},
{"Read", 1, 0, 0, "B", nil},
{"Read", 1, 0, 0, "B", nil},
{"Read", 1, 0, 0, "B", nil},
{"Read", 1, 0, 0, "B", nil},
{"Read", 8, 0, 0, "BBBBCCCC", nil},
}},
{"longBlob.1", []step{
// Test ReadAt with a slice larger than the buffer size.
{"LargeReadAt", 2*rbs - 2, 0, 0, strconv.Itoa(2*rbs - 2), nil},
{"LargeReadAt", 2*rbs - 1, 0, 0, strconv.Itoa(2*rbs - 1), nil},
{"LargeReadAt", 2*rbs + 0, 0, 0, strconv.Itoa(2*rbs + 0), nil},
{"LargeReadAt", 2*rbs + 1, 0, 0, strconv.Itoa(2*rbs + 1), nil},
{"LargeReadAt", 2*rbs + 2, 0, 0, strconv.Itoa(2*rbs + 2), nil},
{"LargeReadAt", 2*rbs - 2, 1, 0, strconv.Itoa(2*rbs - 2), nil},
{"LargeReadAt", 2*rbs - 1, 1, 0, strconv.Itoa(2*rbs - 1), nil},
{"LargeReadAt", 2*rbs + 0, 1, 0, strconv.Itoa(2*rbs + 0), nil},
{"LargeReadAt", 2*rbs + 1, 1, 0, strconv.Itoa(2*rbs + 1), nil},
{"LargeReadAt", 2*rbs + 2, 1, 0, strconv.Itoa(2*rbs + 2), nil},
}},
}
func TestReader(t *testing.T) {
for _, rt := range readerTest {
c := aetesting.FakeSingleContext(t, "blobstore", "FetchData", fakeFetchData)
r := NewReader(c, appengine.BlobKey(rt.blobKey))
for i, step := range rt.step {
var (
got string
gotErr error
n int
offset int64
)
switch step.method {
case "LargeReadAt":
p := make([]byte, step.lenp)
n, gotErr = r.ReadAt(p, step.offset)
got = strconv.Itoa(n)
case "Read":
p := make([]byte, step.lenp)
n, gotErr = r.Read(p)
got = string(p[:n])
case "ReadAt":
p := make([]byte, step.lenp)
n, gotErr = r.ReadAt(p, step.offset)
got = string(p[:n])
case "Seek":
offset, gotErr = r.Seek(step.offset, step.whence)
got = strconv.FormatInt(offset, 10)
default:
t.Fatalf("unknown method: %s", step.method)
}
if gotErr != step.wantErr {
t.Fatalf("%s step %d: got error %v want %v", rt.blobKey, i, gotErr, step.wantErr)
}
if got != step.want {
t.Fatalf("%s step %d: got %q want %q", rt.blobKey, i, got, step.want)
}
}
}
}
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