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/dir_handle_test.go

@@ -0,0 +1,112 @@
+package vfs
+
+import (
+	"io"
+	"os"
+	"testing"
+
+	"github.com/ncw/rclone/fstest"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDirHandleMethods(t *testing.T) {
+	r := fstest.NewRun(t)
+	defer r.Finalise()
+	_, dir, _ := dirCreate(t, r)
+
+	h, err := dir.Open(os.O_RDONLY)
+	require.NoError(t, err)
+	fh, ok := h.(*DirHandle)
+	assert.True(t, ok)
+
+	// String
+	assert.Equal(t, "dir/ (r)", fh.String())
+	assert.Equal(t, "<nil *DirHandle>", (*DirHandle)(nil).String())
+	assert.Equal(t, "<nil *DirHandle.d>", newDirHandle(nil).String())
+
+	// Stat
+	fi, err := fh.Stat()
+	require.NoError(t, err)
+	assert.Equal(t, dir, fi)
+
+	// Node
+	assert.Equal(t, dir, fh.Node())
+
+	// Close
+	require.NoError(t, h.Close())
+	assert.Equal(t, []os.FileInfo(nil), fh.fis)
+}
+
+func TestDirHandleReaddir(t *testing.T) {
+	r := fstest.NewRun(t)
+	defer r.Finalise()
+	vfs := New(r.Fremote, nil)
+
+	file1 := r.WriteObject("dir/file1", "file1 contents", t1)
+	file2 := r.WriteObject("dir/file2", "file2- contents", t2)
+	file3 := r.WriteObject("dir/subdir/file3", "file3-- contents", t3)
+	fstest.CheckItems(t, r.Fremote, file1, file2, file3)
+
+	node, err := vfs.Stat("dir")
+	require.NoError(t, err)
+	dir := node.(*Dir)
+
+	// Read in one chunk
+	fh, err := dir.Open(os.O_RDONLY)
+	require.NoError(t, err)
+
+	fis, err := fh.Readdir(-1)
+	require.NoError(t, err)
+	require.Equal(t, 3, len(fis))
+	assert.Equal(t, "file1", fis[0].Name())
+	assert.Equal(t, "file2", fis[1].Name())
+	assert.Equal(t, "subdir", fis[2].Name())
+	assert.False(t, fis[0].IsDir())
+	assert.False(t, fis[1].IsDir())
+	assert.True(t, fis[2].IsDir())
+
+	require.NoError(t, fh.Close())
+
+	// Read in multiple chunks
+	fh, err = dir.Open(os.O_RDONLY)
+	require.NoError(t, err)
+
+	fis, err = fh.Readdir(2)
+	require.NoError(t, err)
+	require.Equal(t, 2, len(fis))
+	assert.Equal(t, "file1", fis[0].Name())
+	assert.Equal(t, "file2", fis[1].Name())
+	assert.False(t, fis[0].IsDir())
+	assert.False(t, fis[1].IsDir())
+
+	fis, err = fh.Readdir(2)
+	require.NoError(t, err)
+	require.Equal(t, 1, len(fis))
+	assert.Equal(t, "subdir", fis[0].Name())
+	assert.True(t, fis[0].IsDir())
+
+	fis, err = fh.Readdir(2)
+	assert.Equal(t, io.EOF, err)
+	require.Equal(t, 0, len(fis))
+
+	require.NoError(t, fh.Close())
+
+}
+
+func TestDirHandleReaddirnames(t *testing.T) {
+	r := fstest.NewRun(t)
+	defer r.Finalise()
+	_, dir, _ := dirCreate(t, r)
+
+	fh, err := dir.Open(os.O_RDONLY)
+	require.NoError(t, err)
+
+	// Smoke test only since heavy lifting done in Readdir
+	fis, err := fh.Readdirnames(-1)
+	require.NoError(t, err)
+	require.Equal(t, 1, len(fis))
+	assert.Equal(t, "file1", fis[0])
+
+	require.NoError(t, fh.Close())
+}