vfs: add tests and subsequent fixes

* Tests for VFS layer
  * Small fixes found during testing
  * Fix Close, Flush and Release behaviour for ReadFileHandle and WriteFileHandle
  * Fix nil object bugs on File

vfs/createinfo_test.go

@@ -0,0 +1,29 @@
+package vfs
+
+import (
+	"testing"
+	"time"
+
+	"github.com/ncw/rclone/fs"
+	"github.com/ncw/rclone/fstest"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCreateInfo(t *testing.T) {
+	r := fstest.NewRun(t)
+	defer r.Finalise()
+
+	remote := "file/to/be/created"
+	ci := newCreateInfo(r.Fremote, remote)
+
+	// Test methods
+	assert.Equal(t, r.Fremote, ci.Fs())
+	assert.Equal(t, remote, ci.String())
+	assert.Equal(t, remote, ci.Remote())
+	_, err := ci.Hash(fs.HashMD5)
+	assert.Equal(t, fs.ErrHashUnsupported, err)
+	assert.WithinDuration(t, time.Now(), ci.ModTime(), time.Second)
+	assert.Equal(t, int64(0), ci.Size())
+	assert.Equal(t, true, ci.Storable())
+
+}