2 files changed, 23 insertions, 1 deletions
diff --git a/utils/fs/memory/memory.go b/utils/fs/memory/memory.go
index 398ac35..54dd497 100644
--- a/utils/fs/memory/memory.go
+++ b/utils/fs/memory/memory.go
@@ -40,6 +40,7 @@ func (fs *Memory) Open(filename string) (fs.File, error) {
 func (fs *Memory) OpenFile(filename string, flag int, perm os.FileMode) (fs.File, error) {
 	fullpath := fs.Join(fs.base, filename)
 	f, ok := fs.s.files[fullpath]
+
 	if !ok && !isCreate(flag) {
 		return nil, os.ErrNotExist
 	}
@@ -194,7 +195,6 @@ func (f *file) Read(b []byte) (int, error) {
 		return 0, err
 	}
 
-	f.position += int64(n)
 	return n, err
 }
 
diff --git a/utils/fs/test/fs_suite.go b/utils/fs/test/fs_suite.go
index 01d6112..91b2be5 100644
--- a/utils/fs/test/fs_suite.go
+++ b/utils/fs/test/fs_suite.go
@@ -8,6 +8,8 @@ import (
 	"strings"
 	"testing"
 
+	"bytes"
+
 	. "gopkg.in/check.v1"
 	. "gopkg.in/src-d/go-git.v4/utils/fs"
 )
@@ -455,3 +457,23 @@ func (s *FilesystemSuite) TestReadAtOnReadOnly(c *C) {
 	c.Assert(string(b), Equals, "cde")
 	c.Assert(f.Close(), IsNil)
 }
+
+func (s *FilesystemSuite) TestReadWriteLargeFile(c *C) {
+	f, err := s.Fs.Create("foo")
+	c.Assert(err, IsNil)
+
+	size := 1 << 20
+
+	n, err := f.Write(bytes.Repeat([]byte("F"), size))
+	c.Assert(err, IsNil)
+	c.Assert(n, Equals, size)
+
+	err = f.Close()
+	c.Assert(err, IsNil)
+
+	f, err = s.Fs.Open("foo")
+	c.Assert(err, IsNil)
+	b, err := ioutil.ReadAll(f)
+	c.Assert(err, IsNil)
+	c.Assert(len(b), Equals, size)
+}