X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/2c6557f613fcf6cdcebb08c321a5d061aeb780c6..022107bd52092c658208e74161581c6bedda4a5f:/services/keepstore/volume_test.go

diff --git a/services/keepstore/volume_test.go b/services/keepstore/volume_test.go
index 5a17b3a7dc..f64041b048 100644
--- a/services/keepstore/volume_test.go
+++ b/services/keepstore/volume_test.go
@@ -5,6 +5,7 @@
 package keepstore
 
 import (
+	"sync"
 	"time"
 )
 
@@ -38,3 +39,52 @@ type TestableVolume interface {
 	// Clean up, delete temporary files.
 	Teardown()
 }
+
+// brbuffer is like bytes.Buffer, but it implements io.WriterAt.
+// Convenient for testing (volume)BlockRead implementations.
+type brbuffer struct {
+	mtx sync.Mutex
+	buf []byte
+}
+
+func (b *brbuffer) WriteAt(p []byte, offset int64) (int, error) {
+	b.mtx.Lock()
+	defer b.mtx.Unlock()
+	if short := int(offset) + len(p) - len(b.buf); short > 0 {
+		b.buf = append(b.buf, make([]byte, short)...)
+	}
+	return copy(b.buf[offset:], p), nil
+}
+
+func (b *brbuffer) Bytes() []byte {
+	b.mtx.Lock()
+	defer b.mtx.Unlock()
+	return b.buf
+}
+
+func (b *brbuffer) String() string {
+	b.mtx.Lock()
+	defer b.mtx.Unlock()
+	return string(b.buf)
+}
+
+func (b *brbuffer) Len() int {
+	b.mtx.Lock()
+	defer b.mtx.Unlock()
+	return len(b.buf)
+}
+
+func (b *brbuffer) Reset() {
+	b.mtx.Lock()
+	defer b.mtx.Unlock()
+	b.buf = nil
+}
+
+// a brdiscarder is like io.Discard, but it implements
+// io.WriterAt. Convenient for testing (volume)BlockRead
+// implementations when the output is not checked.
+type brdiscarder struct{}
+
+func (brdiscarder) WriteAt(p []byte, offset int64) (int, error) { return len(p), nil }
+
+var brdiscard = brdiscarder{}