isolate: test uploading of individual regular files

client/cmd/isolate/upload_tracker.go

Index: client/cmd/isolate/upload_tracker.go
diff --git a/client/cmd/isolate/upload_tracker.go b/client/cmd/isolate/upload_tracker.go
index 44f00c89fd8d9397e85f9fdb9bfd7ee673918dff..ef098c287ff9bdd7a950ab32b7546b0ab6a4b179 100644
--- a/client/cmd/isolate/upload_tracker.go
+++ b/client/cmd/isolate/upload_tracker.go
@@ -32,6 +32,11 @@ import (
 // limitedOS contains a subset of the functions from the os package.
 type limitedOS interface {
 	Readlink(string) (string, error)
+
+	// Open is like os.Open, but returns an io.ReadCloser since
+	// that's all we need and it's easier to implment with a fake.
+	Open(string) (io.ReadCloser, error)
+
 	openFiler
 }
 
@@ -48,6 +53,10 @@ func (sos standardOS) Readlink(name string) (string, error) {
 	return os.Readlink(name)
 }
 
+func (sos standardOS) Open(name string) (io.ReadCloser, error) {
+	return os.Open(name)
+}
+
 func (sos standardOS) OpenFile(name string, flag int, perm os.FileMode) (io.WriteCloser, error) {
 	return os.OpenFile(name, flag, perm)
 }
@@ -151,7 +160,7 @@ func (ut *UploadTracker) tarAndUploadFiles(smallFiles []*Item) error {
 func (ut *UploadTracker) uploadFiles(files []*Item) error {
 	// Handle the large individually-uploaded files.
 	for _, item := range files {
-		d, err := hashFile(item.Path)
+		d, err := ut.hashFile(item.Path)
 		if err != nil {
 			return err
 		}
@@ -208,6 +217,15 @@ func (ut *UploadTracker) Finalize(isolatedPath string) (IsolatedSummary, error)
 	}, nil
 }
 
+func (ut *UploadTracker) hashFile(path string) (isolated.HexDigest, error) {
+	f, err := ut.lOS.Open(path)
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+	return isolated.Hash(f)
+}
+
 // isolatedFile is an isolated file which is stored in memory.
 // It can produce a corresponding Item, for upload to the server,
 // and also write its contents to the filesystem.