feat: Add support for Write Empty File Behavior (#54)

go.mod

@@ -6,7 +6,7 @@ require (
 	github.com/Azure/azure-pipeline-go v0.2.3
 	github.com/Azure/azure-storage-blob-go v0.14.0
 	github.com/beyondstorage/go-endpoint v1.1.0
-	github.com/beyondstorage/go-integration-test/v4 v4.4.0
+	github.com/beyondstorage/go-integration-test/v4 v4.5.0
 	github.com/beyondstorage/go-storage/v4 v4.7.0
 	github.com/google/uuid v1.3.0
 )

go.sum

@@ -18,8 +18,8 @@ github.com/Xuanwo/templateutils v0.1.0 h1:WpkWOqQtIQ2vAIpJLa727DdN8WtxhUkkbDGa6U
 github.com/Xuanwo/templateutils v0.1.0/go.mod h1:OdE0DJ+CJxDBq6psX5DPV+gOZi8bhuHuVUpPCG++Wb8=
 github.com/beyondstorage/go-endpoint v1.1.0 h1:cpjmQdrAMyaLoT161NIFU/eXcsuMI3xViycid5/mBZg=
 github.com/beyondstorage/go-endpoint v1.1.0/go.mod h1:P2hknaGrziOJJKySv/XnAiVw/d3v12/LZu2gSxEx4nM=
-github.com/beyondstorage/go-integration-test/v4 v4.4.0 h1:wiItWmhoAY71Fp76u6u95jJn5m6swM9N/xNV9mW7nyI=
-github.com/beyondstorage/go-integration-test/v4 v4.4.0/go.mod h1:o0pHhyaRR/OO6QxnRqWW3aFjTycBZjoKSdHKN/JZRjo=
+github.com/beyondstorage/go-integration-test/v4 v4.5.0 h1:PMrB+aWd6yNwlrJSJOjqNLJtujsKderoSkG9/QOEQr0=
+github.com/beyondstorage/go-integration-test/v4 v4.5.0/go.mod h1:o0pHhyaRR/OO6QxnRqWW3aFjTycBZjoKSdHKN/JZRjo=
 github.com/beyondstorage/go-storage/v4 v4.7.0 h1:7hpRFNoPY0vWRSH/p2biD2dUQdZMrs1TuIkkqDefmCE=
 github.com/beyondstorage/go-storage/v4 v4.7.0/go.mod h1:mc9VzBImjXDg1/1sLfta2MJH79elfM6m47ZZvZ+q/Uw=
 github.com/dave/dst v0.26.2 h1:lnxLAKI3tx7MgLNVDirFCsDTlTG9nKTk7GcptKcWSwY=

storage.go

@@ -343,6 +343,14 @@ func (s *Storage) write(ctx context.Context, path string, r io.Reader, size int6
 		return
 	}
 
+	// According to GSP-751, we should allow the user to pass in a nil io.Reader.
+	// ref: https://github.com/beyondstorage/go-storage/blob/master/docs/rfcs/751-write-empty-file-behavior.md
+	if r == nil && size != 0 {
+		return 0, fmt.Errorf("reader is nil but size is not 0")
+	} else {
+		r = io.LimitReader(r, size)
+	}
+
 	rp := s.getAbsPath(path)
 
 	if opt.HasIoCallback {