From ca114f296a69f486dcf7584c2abfbcf80d38c581 Mon Sep 17 00:00:00 2001
From: Aaron Jacobs <jacobsa@google.com>
Date: Wed, 9 Sep 2015 12:21:47 +0000
Subject: [PATCH] Fixed most tests on Linux.

---
 fuseops/ops.go                      |  5 +--
 samples/statfs/statfs_linux_test.go | 49 ++++++++++++-----------------
 samples/statfs/statfs_test.go       | 12 ++++++-
 3 files changed, 34 insertions(+), 32 deletions(-)

diff --git a/fuseops/ops.go b/fuseops/ops.go
index aa56176..eee34c5 100644
--- a/fuseops/ops.go
+++ b/fuseops/ops.go
@@ -46,8 +46,9 @@ type StatFSOp struct {
 	// with the block counts below,  by callers of statfs(2) to infer the file
 	// system's capacity and space availability.
 	//
-	// TODO(jacobsa): Document the range of values accepted on OS X and Linux.
-	// Cite sources in Linux if possible.
+	// On Linux this can be any value, which will be faitfully returned to the
+	// caller of statfs(2) (see the code walk above). On OS X it appears it must
+	// be a power of 2 in [2^9, 2^17].
 	//
 	// On OS X this also affects statfs::f_iosize, which is documented as the
 	// "optimal transfer block size". It does not appear to cause osxfuse to
diff --git a/samples/statfs/statfs_linux_test.go b/samples/statfs/statfs_linux_test.go
index fc4179d..f7cb63d 100644
--- a/samples/statfs/statfs_linux_test.go
+++ b/samples/statfs/statfs_linux_test.go
@@ -16,6 +16,7 @@ package statfs_test
 
 import (
 	"fmt"
+	"math"
 	"syscall"
 
 	"github.com/jacobsa/fuse/fuseops"
@@ -36,8 +37,8 @@ func (t *StatFSTest) Syscall_ZeroValues() {
 	err = syscall.Statfs(t.Dir, &stat)
 	AssertEq(nil, err)
 
-	ExpectEq(4096, stat.Bsize)
-	ExpectEq(65536, stat.Frsize)
+	ExpectEq(0, stat.Bsize)
+	ExpectEq(0, stat.Frsize)
 	ExpectEq(0, stat.Blocks)
 	ExpectEq(0, stat.Bfree)
 	ExpectEq(0, stat.Bavail)
@@ -76,38 +77,28 @@ func (t *StatFSTest) Syscall_NonZeroValues() {
 	ExpectEq(canned.InodesFree, stat.Ffree)
 }
 
-func (t *StatFSTest) UnsupportedBlockSizes() {
+func (t *StatFSTest) WackyBlockSizes() {
 	var err error
 
-	// Test a bunch of block sizes that the OS doesn't support faithfully,
-	// checking what it transforms them too.
-	testCases := []struct {
-		fsBlockSize    uint32
-		expectedBsize  uint32
-		expectedFrsize uint32
-	}{
-		0:  {0, 4096, 65536},
-		1:  {1, 512, 512},
-		2:  {3, 512, 512},
-		3:  {511, 512, 512},
-		4:  {513, 1024, 1024},
-		5:  {1023, 1024, 1024},
-		6:  {4095, 4096, 4096},
-		7:  {1<<17 - 1, 1 << 17, 131072},
-		8:  {1<<17 + 1, 1 << 17, 1 << 18},
-		9:  {1<<18 + 1, 1 << 17, 1 << 19},
-		10: {1<<19 + 1, 1 << 17, 1 << 20},
-		11: {1<<20 + 1, 1 << 17, 1 << 20},
-		12: {1 << 21, 1 << 17, 1 << 20},
-		13: {1 << 30, 1 << 17, 1 << 20},
+	// Test a bunch of weird block sizes that OS X would be cranky about.
+	blockSizes := []uint32{
+		0,
+		1,
+		3,
+		17,
+		1<<20 - 1,
+		1<<20 + 0,
+		1<<20 + 1,
+		math.MaxInt32,
+		math.MaxUint32,
 	}
 
-	for i, tc := range testCases {
-		desc := fmt.Sprintf("Case %d: block size %d", i, tc.fsBlockSize)
+	for _, bs := range blockSizes {
+		desc := fmt.Sprintf("block size %d", bs)
 
 		// Set up.
 		canned := fuseops.StatFSOp{
-			BlockSize: tc.fsBlockSize,
+			BlockSize: bs,
 			Blocks:    10,
 		}
 
@@ -118,7 +109,7 @@ func (t *StatFSTest) UnsupportedBlockSizes() {
 		err = syscall.Statfs(t.Dir, &stat)
 		AssertEq(nil, err)
 
-		ExpectEq(tc.expectedBsize, stat.Bsize, "%s", desc)
-		ExpectEq(tc.expectedFrsize, stat.Frsize, "%s", desc)
+		ExpectEq(bs, stat.Bsize, "%s", desc)
+		ExpectEq(bs, stat.Frsize, "%s", desc)
 	}
 }
diff --git a/samples/statfs/statfs_test.go b/samples/statfs/statfs_test.go
index 5d4c22a..677b53d 100644
--- a/samples/statfs/statfs_test.go
+++ b/samples/statfs/statfs_test.go
@@ -22,6 +22,7 @@ import (
 	"path"
 	"path/filepath"
 	"regexp"
+	"runtime"
 	"strconv"
 	"testing"
 
@@ -190,5 +191,14 @@ func (t *StatFSTest) WriteSize() {
 
 	// Despite the small block size, the OS shouldn't have given us pitifully
 	// small chunks of data.
-	ExpectEq(1<<20, t.fs.MostRecentWriteSize())
+	switch runtime.GOOS {
+	case "linux":
+		ExpectEq(1<<17, t.fs.MostRecentWriteSize())
+
+	case "darwin":
+		ExpectEq(1<<20, t.fs.MostRecentWriteSize())
+
+	default:
+		AddFailure("Unhandled OS: %s", runtime.GOOS)
+	}
 }