Disabled a test for a feature that doesn't work on OS X.

fuseops/ops.go

@@ -456,7 +456,11 @@ type OpenFileOp struct {
 	// a particular inode go through the kernel, set this field to true to
 	// disable this behavior.
 	//
-	// More discussion: http://goo.gl/cafzWF
+	// (More discussion: http://goo.gl/cafzWF)
+	//
+	// Note that on OS X it appears that the behavior is always as if this field
+	// is set to true, regardless of its value, at least for files opened in the
+	// same mode. (Cf. https://github.com/osxfuse/osxfuse/issues/223)
 	KeepPageCache bool
 }
 

samples/cachingfs/caching_fs_test.go

@@ -616,6 +616,12 @@ func (t *PageCacheTest) SingleFileHandle_KeepCache() {
 func (t *PageCacheTest) TwoFileHandles_NoKeepCache() {
 	t.fs.SetKeepCache(false)
 
+	// SetKeepCache(false) doesn't work on OS X. See the notes on
+	// OpenFileOp.KeepPageCache.
+	if runtime.GOOS == "darwin" {
+		return
+	}
+
 	// Open the file.
 	f1, err := os.Open(path.Join(t.Dir, "foo"))
 	AssertEq(nil, err)