local: unit-test the atomicity

local/container_test.go

@@ -2,6 +2,7 @@ package local_test
 
 import (
 	"fmt"
+	"io"
 	"strings"
 	"testing"
 
@@ -60,3 +61,82 @@ func TestItemsPaging(t *testing.T) {
 	is.Equal(err, stow.ErrBadCursor)
 
 }
+
+type chunkOfZero int
+
+func (c *chunkOfZero) Read(b []byte) (n int, err error) {
+	if *c <= 0 {
+		return 0, io.EOF
+	}
+	toFill := len(b)
+	if toFill > int(*c) {
+		toFill = int(*c)
+	}
+	leftBytes := int(*c) - toFill
+	*c = chunkOfZero(leftBytes)
+	for i := 0; i < toFill; i++ {
+		b[i] = 0
+	}
+	return toFill, nil
+}
+
+func TestAtomicWrites(t *testing.T) {
+	is := is.New(t)
+	testDir, teardown, err := setup()
+	is.NoErr(err)
+	defer teardown()
+	cfg := stow.ConfigMap{"path": testDir}
+	l, err := stow.Dial(local.Kind, cfg)
+	is.NoErr(err)
+	is.OK(l)
+
+	container, err := l.Container("one")
+	is.NoErr(err)
+	is.OK(container)
+
+	initialVer := chunkOfZero(1000000)
+	initialItem, err := container.Put("test-file", &initialVer, 1000000, nil)
+	is.NoErr(err)
+	sz, err := initialItem.Size()
+	is.NoErr(err)
+	is.True(sz == 1000000)
+
+	end := make(chan error)
+	go func() {
+		for i := 0; i < 10; i++ {
+			c := chunkOfZero(1000000)
+			_, err := container.Put("test-file", &c, 1000000, nil)
+			if err != nil {
+				end <- err
+			}
+		}
+
+		end <- nil
+	}()
+
+loop:
+	for {
+		items, _, err := container.Items("", "", 10)
+		is.NoErr(err)
+		is.True(len(items) < 10)
+		found := false
+		for _, i := range items {
+			if i.Name() != "test-file" {
+				continue
+			}
+
+			found = true
+			sz, err := i.Size()
+			is.NoErr(err)
+			is.True(sz == 1000000)
+		}
+		is.True(found)
+
+		select {
+		case err := <-end:
+			is.NoErr(err)
+			break loop
+		default:
+		}
+	}
+}