diff --git a/backend_windows_test.go b/backend_windows_test.go
index 0578d60d..8e5ce7f2 100644
--- a/backend_windows_test.go
+++ b/backend_windows_test.go
@@ -53,6 +53,46 @@ func TestRemoveState(t *testing.T) {
 
 // TODO: write test which makes sure the buffer size is set correctly.
 func TestWindowsWithBufferSize(t *testing.T) {
-	w := newWatcher(t, t.TempDir())
-	fmt.Printf("%#v\n", w)
+	getWatch := func(opts ...addOpt) (*watch, error) {
+		w, err := NewWatcher()
+		if err != nil {
+			return nil, err
+		}
+		if err := w.AddWith(t.TempDir(), opts...); err != nil {
+			return nil, err
+		}
+
+		// Hackery to get first (and only) map value.
+		var v indexMap
+		for _, v = range w.watches {
+		}
+		if len(v) != 1 {
+			t.Fatal()
+		}
+		var watch *watch
+		for _, watch = range v {
+		}
+		return watch, nil
+	}
+
+	check := func(w *watch, want int) {
+		if len(w.buf) != want || cap(w.buf) != want {
+			t.Fatalf("want = %d; len = %d; cap = %d", want, len(w.buf), cap(w.buf))
+		}
+	}
+
+	if w, err := getWatch(); err != nil {
+		t.Fatal(err)
+	} else {
+		check(w, 65536)
+	}
+	if w, err := getWatch(WithBufferSize(4096)); err != nil {
+		t.Fatal(err)
+	} else {
+		check(w, 4096)
+	}
+
+	if _, err := getWatch(WithBufferSize(1024)); err == nil || !strings.Contains(err.Error(), "cannot be smaller") {
+		t.Fatal(err)
+	}
 }
diff --git a/fsnotify_test.go b/fsnotify_test.go
index f06fbc16..c78106cd 100644
--- a/fsnotify_test.go
+++ b/fsnotify_test.go
@@ -945,10 +945,6 @@ func TestAdd(t *testing.T) {
 	})
 }
 
-func TestAddWith(t *testing.T) {
-	// TODO: write basic test to ensure AddWith() isn't completely borked.
-}
-
 // TODO: should also check internal state is correct/cleaned up; e.g. no
 //       left-over file descriptors or whatnot.
 func TestRemove(t *testing.T) {