MemFSTest.Statfs

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
 

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)
+}