Split plugin framework into its own package

Signed-off-by: Carlisia <carlisiac@vmware.com>

pkg/plugin/framework/stream_reader_test.go

@@ -0,0 +1,66 @@
+/*
+Copyright 2017, 2019 the Velero contributors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package framework
+
+import (
+	"bytes"
+	"io/ioutil"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+type stringByteReceiver struct {
+	buf       *bytes.Buffer
+	chunkSize int
+}
+
+func (r *stringByteReceiver) Receive() ([]byte, error) {
+	chunk := make([]byte, r.chunkSize)
+
+	n, err := r.buf.Read(chunk)
+	if err != nil {
+		return nil, err
+	}
+
+	return chunk[0:n], nil
+}
+
+func (r *stringByteReceiver) CloseSend() error {
+	r.buf = nil
+	return nil
+}
+
+func TestStreamReader(t *testing.T) {
+	s := "hello world, it's me, streamreader!!!!!"
+
+	rdr := &stringByteReceiver{
+		buf:       bytes.NewBufferString(s),
+		chunkSize: 3,
+	}
+
+	sr := &StreamReadCloser{
+		receive: rdr.Receive,
+		close:   rdr.CloseSend,
+	}
+
+	res, err := ioutil.ReadAll(sr)
+
+	require.Nil(t, err)
+	assert.Equal(t, s, string(res))
+}