fs: make storers implement storage interface

The memory and file storers already almost completely implement the
storage interface.  Add Close methods to make them implement the
interface completely.

Author: bk2204

file_storer.go

@@ -90,6 +90,16 @@ func (fs *fileStorer) Root() string {
 	return fs.root
 }
 
+// Close closes the file storer.
+func (fs *fileStorer) Close() error {
+	return nil
+}
+
+// IsCompressed returns true, because the file storer returns compressed data.
+func (fs *fileStorer) IsCompressed() bool {
+	return true
+}
+
 // open opens a given file.
 func (fs *fileStorer) open(path string, flag int) (*os.File, error) {
 	return os.OpenFile(path, flag, 0)

memory_storer.go

@@ -62,6 +62,16 @@ func (ms *memoryStorer) Open(sha []byte) (f io.ReadCloser, err error) {
 	return ms.fs[key], nil
 }
 
+// Close closes the memory storer.
+func (ms *memoryStorer) Close() error {
+	return nil
+}
+
+// IsCompressed returns true, because the memory storer returns compressed data.
+func (ms *memoryStorer) IsCompressed() bool {
+	return true
+}
+
 // bufCloser wraps a type satisfying the io.ReadWriter interface with a no-op
 // Close() function, thus implementing the io.ReadWriteCloser composite
 // interface.

memory_storer_test.go

@@ -35,6 +35,7 @@ func TestMemoryStorerAcceptsNilEntries(t *testing.T) {
 
 	assert.NotNil(t, ms)
 	assert.Equal(t, 0, len(ms.fs))
+	assert.NoError(t, ms.Close())
 }
 
 func TestMemoryStorerDoesntOpenMissingEntries(t *testing.T) {