diff --git a/fusetesting/stat.go b/fusetesting/stat.go
index 239d6c5..0c647eb 100644
--- a/fusetesting/stat.go
+++ b/fusetesting/stat.go
@@ -57,30 +57,39 @@ func mtimeIsWithin(c interface{}, expected time.Time, d time.Duration) error {
 	return nil
 }
 
-// Match os.FileInfo values that specify a file birth time equal to the given
-// time. On platforms where there is no birth time available, match all
-// os.FileInfo values.
-func BirthtimeIs(expected time.Time) oglematchers.Matcher {
+// Match os.FileInfo values that specify a file birth time within the supplied
+// radius of the given time. On platforms where there is no birth time
+// available, match all os.FileInfo values.
+func BirthtimeIsWithin(
+	expected time.Time,
+	d time.Duration) oglematchers.Matcher {
 	return oglematchers.NewMatcher(
-		func(c interface{}) error { return birthtimeIs(c, expected) },
-		fmt.Sprintf("birthtime is %v", expected))
+		func(c interface{}) error { return birthtimeIsWithin(c, expected, d) },
+		fmt.Sprintf("birthtime is within %v of %v", d, expected))
 }
 
-func birthtimeIs(c interface{}, expected time.Time) error {
+func birthtimeIsWithin(
+	c interface{},
+	expected time.Time,
+	d time.Duration) error {
 	fi, ok := c.(os.FileInfo)
 	if !ok {
 		return fmt.Errorf("which is of type %v", reflect.TypeOf(c))
 	}
 
-	// Check Sys().
-	if sysBirthtime, ok := extractBirthtime(fi.Sys()); ok {
-		if sysBirthtime != expected {
-			d := sysBirthtime.Sub(expected)
-			return fmt.Errorf(
-				"which has Sys() birthtime %v, off by %v",
-				sysBirthtime,
-				d)
-		}
+	t, ok := extractBirthtime(fi.Sys())
+	if !ok {
+		return nil
+	}
+
+	diff := t.Sub(expected)
+	absDiff := diff
+	if absDiff < 0 {
+		absDiff = -absDiff
+	}
+
+	if !(absDiff < d) {
+		return fmt.Errorf("which has birth time %v, off by %v", t, diff)
 	}
 
 	return nil
diff --git a/samples/memfs/memfs_test.go b/samples/memfs/memfs_test.go
index 8ef5544..7d47c4f 100644
--- a/samples/memfs/memfs_test.go
+++ b/samples/memfs/memfs_test.go
@@ -131,7 +131,7 @@ func (t *MemFSTest) Mkdir_OneLevel() {
 	ExpectEq(0, fi.Size())
 	ExpectEq(os.ModeDir|applyUmask(0754), fi.Mode())
 	ExpectThat(fi, fusetesting.MtimeIsWithin(createTime, timeSlop))
-	ExpectThat(fi, fusetesting.BirthtimeIs(createTime))
+	ExpectThat(fi, fusetesting.BirthtimeIsWithin(createTime, timeSlop))
 	ExpectTrue(fi.IsDir())
 
 	ExpectNe(0, stat.Ino)
@@ -187,7 +187,7 @@ func (t *MemFSTest) Mkdir_TwoLevels() {
 	ExpectEq(0, fi.Size())
 	ExpectEq(os.ModeDir|applyUmask(0754), fi.Mode())
 	ExpectThat(fi, fusetesting.MtimeIsWithin(createTime, timeSlop))
-	ExpectThat(fi, fusetesting.BirthtimeIs(createTime))
+	ExpectThat(fi, fusetesting.BirthtimeIsWithin(createTime, timeSlop))
 	ExpectTrue(fi.IsDir())
 
 	ExpectNe(0, stat.Ino)
@@ -296,7 +296,7 @@ func (t *MemFSTest) CreateNewFile_InRoot() {
 	ExpectEq(len(contents), fi.Size())
 	ExpectEq(applyUmask(0400), fi.Mode())
 	ExpectThat(fi, fusetesting.MtimeIsWithin(createTime, timeSlop))
-	ExpectThat(fi, fusetesting.BirthtimeIs(createTime))
+	ExpectThat(fi, fusetesting.BirthtimeIsWithin(createTime, timeSlop))
 	ExpectFalse(fi.IsDir())
 
 	ExpectNe(0, stat.Ino)
@@ -338,7 +338,7 @@ func (t *MemFSTest) CreateNewFile_InSubDir() {
 	ExpectEq(len(contents), fi.Size())
 	ExpectEq(applyUmask(0400), fi.Mode())
 	ExpectThat(fi, fusetesting.MtimeIsWithin(createTime, timeSlop))
-	ExpectThat(fi, fusetesting.BirthtimeIs(createTime))
+	ExpectThat(fi, fusetesting.BirthtimeIsWithin(createTime, timeSlop))
 	ExpectFalse(fi.IsDir())
 
 	ExpectNe(0, stat.Ino)
@@ -385,7 +385,7 @@ func (t *MemFSTest) ModifyExistingFile_InRoot() {
 	ExpectEq(len("Hello, world!"), fi.Size())
 	ExpectEq(applyUmask(0600), fi.Mode())
 	ExpectThat(fi, fusetesting.MtimeIsWithin(modifyTime, timeSlop))
-	ExpectThat(fi, fusetesting.BirthtimeIs(createTime))
+	ExpectThat(fi, fusetesting.BirthtimeIsWithin(createTime, timeSlop))
 	ExpectFalse(fi.IsDir())
 
 	ExpectNe(0, stat.Ino)
@@ -437,7 +437,7 @@ func (t *MemFSTest) ModifyExistingFile_InSubDir() {
 	ExpectEq(len("Hello, world!"), fi.Size())
 	ExpectEq(applyUmask(0600), fi.Mode())
 	ExpectThat(fi, fusetesting.MtimeIsWithin(modifyTime, timeSlop))
-	ExpectThat(fi, fusetesting.BirthtimeIs(createTime))
+	ExpectThat(fi, fusetesting.BirthtimeIsWithin(createTime, timeSlop))
 	ExpectFalse(fi.IsDir())
 
 	ExpectNe(0, stat.Ino)