From 284ddf44b02139a1f487459c76a18b8099d1328e Mon Sep 17 00:00:00 2001
From: Aaron Jacobs <jacobsa@google.com>
Date: Wed, 9 Sep 2015 09:28:05 +1000
Subject: [PATCH] MemFSTest.Statfs

---
 samples/memfs/memfs.go      |  6 ++++++
 samples/memfs/memfs_test.go | 24 ++++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/samples/memfs/memfs.go b/samples/memfs/memfs.go
index 1d4032c..4e8c3a5 100644
--- a/samples/memfs/memfs.go
+++ b/samples/memfs/memfs.go
@@ -28,6 +28,12 @@ import (
 	"github.com/jacobsa/syncutil"
 )
 
+// The capacities of the file system, as reported to statfs(2).
+const (
+	Capacity_Bytes = 1 << 50
+	Capacity_Files = 1 << 30
+)
+
 type memFS struct {
 	fuseutil.NotImplementedFileSystem
 
diff --git a/samples/memfs/memfs_test.go b/samples/memfs/memfs_test.go
index 7d47c4f..0a7ea29 100644
--- a/samples/memfs/memfs_test.go
+++ b/samples/memfs/memfs_test.go
@@ -1614,3 +1614,27 @@ func (t *MemFSTest) RenameNonExistentFile() {
 	err = os.Rename(path.Join(t.Dir, "foo"), path.Join(t.Dir, "bar"))
 	ExpectThat(err, Error(HasSubstr("no such file")))
 }
+
+func (t *MemFSTest) Statfs() {
+	var err error
+	var stat syscall.Statfs_t
+
+	// Write a few bytes of file content.
+	const content = "taco"
+
+	err = ioutil.WriteFile(path.Join(t.Dir, "foo"), []byte(content), 0400)
+	AssertEq(nil, err)
+
+	// Stat the file system.
+	err = syscall.Statfs(t.Dir, &stat)
+	AssertEq(nil, err)
+
+	ExpectEq(1, stat.Bsize)
+
+	ExpectEq(memfs.Capacity_Bytes, stat.Blocks)
+	ExpectEq(memfs.Capacity_Bytes-len(content), stat.Bfree)
+	ExpectEq(stat.Bfree, stat.Bavail)
+
+	ExpectEq(memfs.Capacity_Files, stat.Files)
+	ExpectEq(memfs.Capacity_Files-2, stat.Ffree)
+}