func CommonTestMerge(t *testing.T, s store.KVStore) {
testKey := []byte("k1")
data := []struct {
key []byte
val []byte
}{
{testKey, encodeUint64(1)},
{testKey, encodeUint64(1)},
}
// open a writer
writer, err := s.Writer()
if err != nil {
t.Fatal(err)
}
// write the data
batch := writer.NewBatch()
for _, row := range data {
batch.Merge(row.key, row.val)
}
err = writer.ExecuteBatch(batch)
if err != nil {
t.Fatal(err)
}
// close the writer
err = writer.Close()
if err != nil {
t.Fatal(err)
}
// open a reader
reader, err := s.Reader()
if err != nil {
t.Fatal(err)
}
// read key
returnedVal, err := reader.Get(testKey)
if err != nil {
t.Fatal(err)
}
// check the value
mergedval := binary.LittleEndian.Uint64(returnedVal)
if mergedval != 2 {
t.Errorf("expected 2, got %d", mergedval)
}
// close the reader
err = reader.Close()
if err != nil {
t.Fatal(err)
}
}
func cleanup(t *testing.T, s store.KVStore) {
err := s.Close()
if err != nil {
t.Fatal(err)
}
err = os.RemoveAll("test")
if err != nil {
t.Fatal(err)
}
}
// NullTestKVStore has very different expectations
// compared to CommonTestKVStore
func NullTestKVStore(t *testing.T, s store.KVStore) {
writer, err := s.Writer()
if err != nil {
t.Error(err)
}
batch := writer.NewBatch()
batch.Set([]byte("b"), []byte("val-b"))
batch.Set([]byte("c"), []byte("val-c"))
batch.Set([]byte("d"), []byte("val-d"))
batch.Set([]byte("e"), []byte("val-e"))
batch.Set([]byte("f"), []byte("val-f"))
batch.Set([]byte("g"), []byte("val-g"))
batch.Set([]byte("h"), []byte("val-h"))
batch.Set([]byte("i"), []byte("val-i"))
batch.Set([]byte("j"), []byte("val-j"))
err = writer.ExecuteBatch(batch)
if err != nil {
t.Fatal(err)
}
err = writer.Close()
if err != nil {
t.Fatal(err)
}
reader, err := s.Reader()
if err != nil {
t.Error(err)
}
defer func() {
err := reader.Close()
if err != nil {
t.Fatal(err)
}
}()
it := reader.RangeIterator([]byte("b"), nil)
key, val, valid := it.Current()
if valid {
t.Fatalf("valid true, expected false")
}
if key != nil {
t.Fatalf("expected key nil, got %s", key)
}
if val != nil {
t.Fatalf("expected value nil, got %s", val)
}
err = it.Close()
if err != nil {
t.Fatal(err)
}
err = s.Close()
if err != nil {
t.Fatal(err)
}
}
func batchWriteRows(s store.KVStore, rows []testRow) error {
// open a writer
writer, err := s.Writer()
if err != nil {
return err
}
// write the data
batch := writer.NewBatch()
for _, row := range rows {
batch.Set(row.key, row.val)
}
err = writer.ExecuteBatch(batch)
if err != nil {
return err
}
// close the writer
err = writer.Close()
if err != nil {
return err
}
return nil
}
func cleanup(t *testing.T, s store.KVStore) {
err := s.Close()
if err != nil {
t.Fatal(err)
}
}
func CommonTestKVCrud(t *testing.T, s store.KVStore) {
writer, err := s.Writer()
if err != nil {
t.Error(err)
}
batch := writer.NewBatch()
batch.Set([]byte("a"), []byte("val-a"))
batch.Set([]byte("z"), []byte("val-z"))
batch.Delete([]byte("z"))
err = writer.ExecuteBatch(batch)
if err != nil {
t.Fatal(err)
}
batch.Reset()
batch.Set([]byte("b"), []byte("val-b"))
batch.Set([]byte("c"), []byte("val-c"))
batch.Set([]byte("d"), []byte("val-d"))
batch.Set([]byte("e"), []byte("val-e"))
batch.Set([]byte("f"), []byte("val-f"))
batch.Set([]byte("g"), []byte("val-g"))
batch.Set([]byte("h"), []byte("val-h"))
batch.Set([]byte("i"), []byte("val-i"))
batch.Set([]byte("j"), []byte("val-j"))
err = writer.ExecuteBatch(batch)
if err != nil {
t.Fatal(err)
}
err = writer.Close()
if err != nil {
t.Fatal(err)
}
reader, err := s.Reader()
if err != nil {
t.Error(err)
}
defer func() {
err := reader.Close()
if err != nil {
t.Fatal(err)
}
}()
it := reader.RangeIterator([]byte("b"), nil)
key, val, valid := it.Current()
if !valid {
t.Fatalf("valid false, expected true")
}
if string(key) != "b" {
t.Fatalf("expected key b, got %s", key)
}
if string(val) != "val-b" {
t.Fatalf("expected value val-b, got %s", val)
}
it.Next()
key, val, valid = it.Current()
if !valid {
t.Fatalf("valid false, expected true")
}
if string(key) != "c" {
t.Fatalf("expected key c, got %s", key)
}
if string(val) != "val-c" {
t.Fatalf("expected value val-c, got %s", val)
}
it.Seek([]byte("i"))
key, val, valid = it.Current()
if !valid {
t.Fatalf("valid false, expected true")
}
if string(key) != "i" {
t.Fatalf("expected key i, got %s", key)
}
if string(val) != "val-i" {
t.Fatalf("expected value val-i, got %s", val)
}
err = it.Close()
if err != nil {
t.Fatal(err)
}
}
// CommonTestReaderOwnsGetBytes attempts to mutate the returned bytes
// first, while the reader is still open, second after that reader is
// closed, then the original key is read again, to ensure these
// modifications did not cause panic, or mutate the stored value
func CommonTestReaderOwnsGetBytes(t *testing.T, s store.KVStore) {
originalKey := []byte("key")
originalVal := []byte("val")
// open a writer
writer, err := s.Writer()
if err != nil {
t.Fatal(err)
}
// write key/val
batch := writer.NewBatch()
batch.Set(originalKey, originalVal)
err = writer.ExecuteBatch(batch)
if err != nil {
t.Fatal(err)
}
// close the writer
err = writer.Close()
if err != nil {
t.Fatal(err)
}
// open a reader
reader, err := s.Reader()
if err != nil {
t.Fatal(err)
}
// read key
returnedVal, err := reader.Get(originalKey)
if err != nil {
t.Fatal(err)
}
// check that it is the expected value
if !reflect.DeepEqual(returnedVal, originalVal) {
t.Fatalf("expected value: %v for '%s', got %v", originalVal, originalKey, returnedVal)
}
// mutate the returned value with reader still open
for i := range returnedVal {
returnedVal[i] = '1'
}
// read the key again
returnedVal2, err := reader.Get(originalKey)
if err != nil {
t.Fatal(err)
}
// check that it is the expected value
if !reflect.DeepEqual(returnedVal2, originalVal) {
t.Fatalf("expected value: %v for '%s', got %v", originalVal, originalKey, returnedVal2)
}
// close the reader
err = reader.Close()
if err != nil {
t.Fatal(err)
}
// mutate the original returned value again
for i := range returnedVal {
returnedVal[i] = '2'
}
// open another reader
reader, err = s.Reader()
if err != nil {
t.Fatal(err)
}
// read the key again
returnedVal3, err := reader.Get(originalKey)
if err != nil {
t.Fatal(err)
}
// check that it is the expected value
if !reflect.DeepEqual(returnedVal3, originalVal) {
t.Fatalf("expected value: %v for '%s', got %v", originalVal, originalKey, returnedVal3)
}
// close the reader
err = reader.Close()
if err != nil {
t.Fatal(err)
}
// finally check that the value we mutated still has what we set it to
for i := range returnedVal {
if returnedVal[i] != '2' {
t.Errorf("expected byte to be '2', got %v", returnedVal[i])
}
}
}
func CommonTestWriterOwnsBytes(t *testing.T, s store.KVStore) {
keyBuffer := make([]byte, 5)
valBuffer := make([]byte, 5)
// open a writer
writer, err := s.Writer()
if err != nil {
t.Fatal(err)
}
// write key/val pairs reusing same buffer
batch := writer.NewBatch()
for i := 0; i < 10; i++ {
keyBuffer[0] = 'k'
keyBuffer[1] = 'e'
keyBuffer[2] = 'y'
keyBuffer[3] = '-'
keyBuffer[4] = byte('0' + i)
valBuffer[0] = 'v'
valBuffer[1] = 'a'
valBuffer[2] = 'l'
valBuffer[3] = '-'
valBuffer[4] = byte('0' + i)
batch.Set(keyBuffer, valBuffer)
}
err = writer.ExecuteBatch(batch)
if err != nil {
t.Fatal(err)
}
// close the writer
err = writer.Close()
if err != nil {
t.Fatal(err)
}
// open a reader
reader, err := s.Reader()
if err != nil {
t.Fatal(err)
}
// check that we can read back what we expect
allks := make([][]byte, 0)
allvs := make([][]byte, 0)
iter := reader.RangeIterator(nil, nil)
for iter.Valid() {
// if we want to keep bytes from iteration we must copy
k := iter.Key()
copyk := make([]byte, len(k))
copy(copyk, k)
allks = append(allks, copyk)
v := iter.Key()
copyv := make([]byte, len(v))
copy(copyv, v)
allvs = append(allvs, copyv)
iter.Next()
}
err = iter.Close()
if err != nil {
t.Fatal(err)
}
if len(allks) != 10 {
t.Fatalf("expected 10 k/v pairs, got %d", len(allks))
}
for i, key := range allks {
val := allvs[i]
if !bytes.HasSuffix(key, []byte{byte('0' + i)}) {
t.Errorf("expected key %v to end in %d", key, []byte{byte('0' + i)})
}
if !bytes.HasSuffix(val, []byte{byte('0' + i)}) {
t.Errorf("expected val %v to end in %d", val, []byte{byte('0' + i)})
}
}
// close the reader
err = reader.Close()
if err != nil {
t.Fatal(err)
}
// open a writer
writer, err = s.Writer()
if err != nil {
t.Fatal(err)
}
// now delete using same approach
batch = writer.NewBatch()
for i := 0; i < 10; i++ {
keyBuffer[0] = 'k'
keyBuffer[1] = 'e'
keyBuffer[2] = 'y'
keyBuffer[3] = '-'
keyBuffer[4] = byte('0' + i)
batch.Delete(keyBuffer)
}
err = writer.ExecuteBatch(batch)
if err != nil {
t.Fatal(err)
}
// close the writer
err = writer.Close()
if err != nil {
t.Fatal(err)
}
// open a reader
reader, err = s.Reader()
if err != nil {
t.Fatal(err)
}
// check that we can read back what we expect
allks = make([][]byte, 0)
iter = reader.RangeIterator(nil, nil)
for iter.Valid() {
// if we want to keep bytes from iteration we must copy
k := iter.Key()
copyk := make([]byte, len(k))
copy(copyk, k)
allks = append(allks, copyk)
v := iter.Key()
copyv := make([]byte, len(v))
copy(copyv, v)
allvs = append(allvs, copyv)
iter.Next()
}
err = iter.Close()
if err != nil {
t.Fatal(err)
}
if len(allks) != 0 {
t.Fatalf("expected 0 k/v pairs remaining, got %d", len(allks))
}
// close the reader
err = reader.Close()
if err != nil {
t.Fatal(err)
}
}
func CommonTestPrefixIterator(t *testing.T, s store.KVStore) {
data := []testRow{
{[]byte("apple"), []byte("val")},
{[]byte("cat1"), []byte("val")},
{[]byte("cat2"), []byte("val")},
{[]byte("cat3"), []byte("val")},
{[]byte("dog1"), []byte("val")},
{[]byte("dog2"), []byte("val")},
{[]byte("dog4"), []byte("val")},
{[]byte("elephant"), []byte("val")},
}
expectedCats := [][]byte{
[]byte("cat1"),
[]byte("cat2"),
[]byte("cat3"),
}
expectedDogs := [][]byte{
[]byte("dog1"),
// we seek to "dog3" and ensure it skips over "dog2"
// but still finds "dog4" even though there was no "dog3"
[]byte("dog4"),
}
err := batchWriteRows(s, data)
if err != nil {
t.Fatal(err)
}
// open a reader
reader, err := s.Reader()
if err != nil {
t.Fatal(err)
}
// get a prefix reader
cats := make([][]byte, 0)
iter := reader.PrefixIterator([]byte("cat"))
for iter.Valid() {
// if we want to keep bytes from iteration we must copy
k := iter.Key()
copyk := make([]byte, len(k))
copy(copyk, k)
cats = append(cats, copyk)
iter.Next()
}
err = iter.Close()
if err != nil {
t.Fatal(err)
}
// check that we found all the cats
if !reflect.DeepEqual(cats, expectedCats) {
t.Fatalf("expected cats %v, got %v", expectedCats, cats)
}
// get a prefix reader
dogs := make([][]byte, 0)
iter = reader.PrefixIterator([]byte("dog"))
for iter.Valid() {
// if we want to keep bytes from iteration we must copy
k := iter.Key()
copyk := make([]byte, len(k))
copy(copyk, k)
dogs = append(dogs, copyk)
if len(dogs) < 2 {
iter.Seek([]byte("dog3"))
} else {
iter.Next()
}
}
err = iter.Close()
if err != nil {
t.Fatal(err)
}
// check that we found the expected dogs
if !reflect.DeepEqual(dogs, expectedDogs) {
t.Fatalf("expected dogs %v, got %v", expectedDogs, dogs)
}
// close the reader
err = reader.Close()
if err != nil {
t.Fatal(err)
}
}
func CommonTestRangeIteratorSeek(t *testing.T, s store.KVStore) {
data := []testRow{
{[]byte("a1"), []byte("val")},
{[]byte("b1"), []byte("val")},
{[]byte("c1"), []byte("val")},
{[]byte("d1"), []byte("val")},
{[]byte("e1"), []byte("val")},
}
err := batchWriteRows(s, data)
if err != nil {
t.Fatal(err)
}
// open a reader
reader, err := s.Reader()
if err != nil {
t.Fatal(err)
}
// get an iterator on a central subset of the data
start := []byte("b1")
end := []byte("d1")
iter := reader.RangeIterator(start, end)
// seek before, at and after every possible key
targets := [][]byte{}
for _, row := range data {
prefix := string(row.key[:1])
targets = append(targets, []byte(prefix+"0"))
targets = append(targets, []byte(prefix+"1"))
targets = append(targets, []byte(prefix+"2"))
}
for _, target := range targets {
found := []string{}
for iter.Seek(target); iter.Valid(); iter.Next() {
found = append(found, string(iter.Key()))
if len(found) > len(data) {
t.Fatalf("enumerated more than data keys after seeking to %s",
string(target))
}
}
wanted := []string{}
for _, row := range data {
if bytes.Compare(row.key, start) < 0 ||
bytes.Compare(row.key, target) < 0 ||
bytes.Compare(row.key, end) >= 0 {
continue
}
wanted = append(wanted, string(row.key))
}
fs := strings.Join(found, ", ")
ws := strings.Join(wanted, ", ")
if fs != ws {
t.Fatalf("iterating from %s returned [%s] instead of [%s]",
string(target), fs, ws)
}
}
err = iter.Close()
if err != nil {
t.Fatal(err)
}
if err != nil {
t.Fatal(err)
}
// close the reader
err = reader.Close()
if err != nil {
t.Fatal(err)
}
}
func CommonTestRangeIterator(t *testing.T, s store.KVStore) {
data := []testRow{
{[]byte("a1"), []byte("val")},
{[]byte("b1"), []byte("val")},
{[]byte("b2"), []byte("val")},
{[]byte("b3"), []byte("val")},
{[]byte("c1"), []byte("val")},
{[]byte("c2"), []byte("val")},
{[]byte("c4"), []byte("val")},
{[]byte("d1"), []byte("val")},
}
expectedAll := make([][]byte, 0)
expectedBToC := make([][]byte, 0)
expectedCToDSeek3 := make([][]byte, 0)
expectedCToEnd := make([][]byte, 0)
for _, row := range data {
expectedAll = append(expectedAll, row.key)
if bytes.HasPrefix(row.key, []byte("b")) {
expectedBToC = append(expectedBToC, row.key)
}
if bytes.HasPrefix(row.key, []byte("c")) && !bytes.HasSuffix(row.key, []byte("2")) {
expectedCToDSeek3 = append(expectedCToDSeek3, row.key)
}
if bytes.Compare(row.key, []byte("c")) > 0 {
expectedCToEnd = append(expectedCToEnd, row.key)
}
}
err := batchWriteRows(s, data)
if err != nil {
t.Fatal(err)
}
// open a reader
reader, err := s.Reader()
if err != nil {
t.Fatal(err)
}
// get a range iterator (all)
all := make([][]byte, 0)
iter := reader.RangeIterator(nil, nil)
for iter.Valid() {
// if we want to keep bytes from iteration we must copy
k := iter.Key()
copyk := make([]byte, len(k))
copy(copyk, k)
all = append(all, copyk)
iter.Next()
}
err = iter.Close()
if err != nil {
t.Fatal(err)
}
// check that we found all
if !reflect.DeepEqual(all, expectedAll) {
t.Fatalf("expected all %v, got %v", expectedAll, all)
}
// get range iterator from b - c
bToC := make([][]byte, 0)
iter = reader.RangeIterator([]byte("b"), []byte("c"))
for iter.Valid() {
// if we want to keep bytes from iteration we must copy
k := iter.Key()
copyk := make([]byte, len(k))
copy(copyk, k)
bToC = append(bToC, copyk)
iter.Next()
}
err = iter.Close()
if err != nil {
t.Fatal(err)
}
// check that we found b-c
if !reflect.DeepEqual(bToC, expectedBToC) {
t.Fatalf("expected b-c %v, got %v", expectedBToC, bToC)
}
// get range iterator from c - d, but seek to 'c3'
cToDSeek3 := make([][]byte, 0)
iter = reader.RangeIterator([]byte("c"), []byte("d"))
for iter.Valid() {
// if we want to keep bytes from iteration we must copy
k := iter.Key()
copyk := make([]byte, len(k))
copy(copyk, k)
cToDSeek3 = append(cToDSeek3, copyk)
if len(cToDSeek3) < 2 {
iter.Seek([]byte("c3"))
} else {
iter.Next()
}
}
err = iter.Close()
if err != nil {
t.Fatal(err)
}
// check that we found c-d with seek to c3
if !reflect.DeepEqual(cToDSeek3, expectedCToDSeek3) {
t.Fatalf("expected b-c %v, got %v", expectedCToDSeek3, cToDSeek3)
}
// get range iterator from c to the end
cToEnd := make([][]byte, 0)
iter = reader.RangeIterator([]byte("c"), nil)
for iter.Valid() {
// if we want to keep bytes from iteration we must copy
k := iter.Key()
copyk := make([]byte, len(k))
copy(copyk, k)
cToEnd = append(cToEnd, copyk)
iter.Next()
}
err = iter.Close()
if err != nil {
t.Fatal(err)
}
// check that we found c to end
if !reflect.DeepEqual(cToEnd, expectedCToEnd) {
t.Fatalf("expected b-c %v, got %v", expectedCToEnd, cToEnd)
}
// close the reader
err = reader.Close()
if err != nil {
t.Fatal(err)
}
}
func CommonTestPrefixIteratorSeek(t *testing.T, s store.KVStore) {
data := []testRow{
{[]byte("a"), []byte("val")},
{[]byte("b1"), []byte("val")},
{[]byte("b2"), []byte("val")},
{[]byte("b3"), []byte("val")},
{[]byte("c"), []byte("val")},
}
err := batchWriteRows(s, data)
if err != nil {
t.Fatal(err)
}
// open a reader
reader, err := s.Reader()
if err != nil {
t.Fatal(err)
}
defer func() {
err := reader.Close()
if err != nil {
t.Fatal(err)
}
}()
// get an iterator on a central subset of the data
iter := reader.PrefixIterator([]byte("b"))
defer func() {
err := iter.Close()
if err != nil {
t.Fatal(err)
}
}()
// check that all keys have prefix
found := []string{}
for ; iter.Valid(); iter.Next() {
found = append(found, string(iter.Key()))
}
for _, f := range found {
if !strings.HasPrefix(f, "b") {
t.Errorf("got key '%s' that doesn't have correct prefix", f)
}
}
if len(found) != 3 {
t.Errorf("expected 3 keys with prefix, got %d", len(found))
}
// now try to seek before the prefix and repeat
found = []string{}
for iter.Seek([]byte("a")); iter.Valid(); iter.Next() {
found = append(found, string(iter.Key()))
}
for _, f := range found {
if !strings.HasPrefix(f, "b") {
t.Errorf("got key '%s' that doesn't have correct prefix", f)
}
}
if len(found) != 3 {
t.Errorf("expected 3 keys with prefix, got %d", len(found))
}
// now try to seek after the prefix and repeat
found = []string{}
for iter.Seek([]byte("c")); iter.Valid(); iter.Next() {
found = append(found, string(iter.Key()))
}
for _, f := range found {
if !strings.HasPrefix(f, "b") {
t.Errorf("got key '%s' that doesn't have correct prefix", f)
}
}
if len(found) != 0 {
t.Errorf("expected 0 keys with prefix, got %d", len(found))
}
}
func CommonTestReaderIsolation(t *testing.T, s store.KVStore) {
// insert a kv pair
writer, err := s.Writer()
if err != nil {
t.Error(err)
}
// **************************************************
// this is a hack only required for BoltDB
// however its harmless so to keep the tests
// the same everywhere, we include it here
//
// this is a hack to try to pre-emptively overflow
// boltdb writes *MAY* block a long reader
// in particular, if the write requires additional
// allocation, it must acquire the same lock as
// the reader, thus cannot continue until that
// reader is closed.
// in general this is not a problem for bleve
// (though it may affect performance in some cases)
// but it is a problem for this test which attempts
// to easily verify that readers are isolated
// this hack writes enough initial data such that
// the subsequent writes do not require additional
// space
hackSize := 1000
batch := writer.NewBatch()
for i := 0; i < hackSize; i++ {
k := fmt.Sprintf("x%d", i)
batch.Set([]byte(k), []byte("filler"))
}
err = writer.ExecuteBatch(batch)
if err != nil {
t.Fatal(err)
}
// **************************************************
batch = writer.NewBatch()
batch.Set([]byte("a"), []byte("val-a"))
err = writer.ExecuteBatch(batch)
if err != nil {
t.Fatal(err)
}
err = writer.Close()
if err != nil {
t.Fatal(err)
}
// create an isolated reader
reader, err := s.Reader()
if err != nil {
t.Error(err)
}
defer func() {
err := reader.Close()
if err != nil {
t.Fatal(err)
}
}()
// verify that we see the value already inserted
val, err := reader.Get([]byte("a"))
if err != nil {
t.Error(err)
}
if !reflect.DeepEqual(val, []byte("val-a")) {
t.Errorf("expected val-a, got nil")
}
// verify that an iterator sees it
count := 0
it := reader.RangeIterator([]byte{0}, []byte{'x'})
defer func() {
err := it.Close()
if err != nil {
t.Fatal(err)
}
}()
for it.Valid() {
it.Next()
count++
}
if count != 1 {
t.Errorf("expected iterator to see 1, saw %d", count)
}
// add something after the reader was created
writer, err = s.Writer()
if err != nil {
t.Error(err)
}
batch = writer.NewBatch()
batch.Set([]byte("b"), []byte("val-b"))
err = writer.ExecuteBatch(batch)
if err != nil {
t.Fatal(err)
}
err = writer.Close()
if err != nil {
t.Fatal(err)
}
// ensure that a newer reader sees it
newReader, err := s.Reader()
if err != nil {
t.Error(err)
}
defer func() {
err := newReader.Close()
if err != nil {
t.Fatal(err)
}
}()
val, err = newReader.Get([]byte("b"))
if err != nil {
t.Error(err)
}
if !reflect.DeepEqual(val, []byte("val-b")) {
t.Errorf("expected val-b, got nil")
}
// ensure that the direct iterator sees it
count = 0
it2 := newReader.RangeIterator([]byte{0}, []byte{'x'})
defer func() {
err := it2.Close()
if err != nil {
t.Fatal(err)
}
}()
for it2.Valid() {
it2.Next()
count++
}
if count != 2 {
t.Errorf("expected iterator to see 2, saw %d", count)
}
// but that the isolated reader does not
val, err = reader.Get([]byte("b"))
if err != nil {
t.Error(err)
}
if val != nil {
t.Errorf("expected nil, got %v", val)
}
// and ensure that the iterator on the isolated reader also does not
count = 0
it3 := reader.RangeIterator([]byte{0}, []byte{'x'})
defer func() {
err := it3.Close()
if err != nil {
t.Fatal(err)
}
}()
for it3.Valid() {
it3.Next()
count++
}
if count != 1 {
t.Errorf("expected iterator to see 1, saw %d", count)
}
}