diff --git a/storagedriver/filesystem/driver.go b/storagedriver/filesystem/driver.go
index 6fb56891b..05ec6175b 100644
--- a/storagedriver/filesystem/driver.go
+++ b/storagedriver/filesystem/driver.go
@@ -82,6 +82,10 @@ func (d *Driver) PutContent(subPath string, contents []byte) error {
 // ReadStream retrieves an io.ReadCloser for the content stored at "path" with a
 // given byte offset.
 func (d *Driver) ReadStream(path string, offset int64) (io.ReadCloser, error) {
+	if offset < 0 {
+		return nil, storagedriver.InvalidOffsetError{Path: path, Offset: offset}
+	}
+
 	file, err := os.OpenFile(d.fullPath(path), os.O_RDONLY, 0644)
 	if err != nil {
 		if os.IsNotExist(err) {
diff --git a/storagedriver/inmemory/driver.go b/storagedriver/inmemory/driver.go
index b6bdc2588..0b68e0210 100644
--- a/storagedriver/inmemory/driver.go
+++ b/storagedriver/inmemory/driver.go
@@ -83,6 +83,10 @@ func (d *Driver) ReadStream(path string, offset int64) (io.ReadCloser, error) {
 	d.mutex.RLock()
 	defer d.mutex.RUnlock()
 
+	if offset < 0 {
+		return nil, storagedriver.InvalidOffsetError{Path: path, Offset: offset}
+	}
+
 	path = d.normalize(path)
 	found := d.root.find(path)
 
diff --git a/storagedriver/testsuites/testsuites.go b/storagedriver/testsuites/testsuites.go
index 6a51cd19c..0967e2dbe 100644
--- a/storagedriver/testsuites/testsuites.go
+++ b/storagedriver/testsuites/testsuites.go
@@ -2,6 +2,7 @@ package testsuites
 
 import (
 	"bytes"
+	"io"
 	"io/ioutil"
 	"math/rand"
 	"os"
@@ -209,6 +210,43 @@ func (suite *DriverSuite) TestReadStreamWithOffset(c *check.C) {
 	readContents, err = ioutil.ReadAll(reader)
 	c.Assert(err, check.IsNil)
 	c.Assert(readContents, check.DeepEquals, contentsChunk3)
+
+	// Ensure we get invalid offest for negative offsets.
+	reader, err = suite.StorageDriver.ReadStream(filename, -1)
+	c.Assert(err, check.FitsTypeOf, storagedriver.InvalidOffsetError{})
+	c.Assert(err.(storagedriver.InvalidOffsetError).Offset, check.Equals, int64(-1))
+	c.Assert(err.(storagedriver.InvalidOffsetError).Path, check.Equals, filename)
+	c.Assert(reader, check.IsNil)
+
+	// Read past the end of the content and make sure we get a reader that
+	// returns 0 bytes and io.EOF
+	reader, err = suite.StorageDriver.ReadStream(filename, chunkSize*3)
+	c.Assert(err, check.IsNil)
+	defer reader.Close()
+
+	buf := make([]byte, chunkSize)
+	n, err := reader.Read(buf)
+	c.Assert(err, check.Equals, io.EOF)
+	c.Assert(n, check.Equals, 0)
+
+	// Check the N-1 boundary condition, ensuring we get 1 byte then io.EOF.
+	reader, err = suite.StorageDriver.ReadStream(filename, chunkSize*3-1)
+	c.Assert(err, check.IsNil)
+	defer reader.Close()
+
+	n, err = reader.Read(buf)
+	c.Assert(n, check.Equals, 1)
+
+	// We don't care whether the io.EOF comes on the this read or the first
+	// zero read, but the only error acceptable here is io.EOF.
+	if err != nil {
+		c.Assert(err, check.Equals, io.EOF)
+	}
+
+	// Any more reads should result in zero bytes and io.EOF
+	n, err = reader.Read(buf)
+	c.Assert(n, check.Equals, 0)
+	c.Assert(err, check.Equals, io.EOF)
 }
 
 // TestContinueStreamAppend tests that a stream write can be appended to without
@@ -329,6 +367,11 @@ func (suite *DriverSuite) TestList(c *check.C) {
 
 	sort.Strings(keys)
 	c.Assert(keys, check.DeepEquals, childFiles)
+
+	// A few checks to add here (check out #819 for more discussion on this):
+	// 1. Ensure that all paths are absolute.
+	// 2. Ensure that listings only include direct children.
+	// 3. Ensure that we only respond to directory listings that end with a slash (maybe?).
 }
 
 // TestMove checks that a moved object no longer exists at the source path and