diff --git a/cmd/restic/exclude_test.go b/cmd/restic/exclude_test.go
index bc8c29866..c7bec4352 100644
--- a/cmd/restic/exclude_test.go
+++ b/cmd/restic/exclude_test.go
@@ -318,3 +318,47 @@ func TestIsExcludedByFileSize(t *testing.T) {
 		}
 	}
 }
+
+func TestDeviceMap(t *testing.T) {
+	deviceMap := DeviceMap{
+		filepath.FromSlash("/"):          1,
+		filepath.FromSlash("/usr/local"): 5,
+	}
+
+	var tests = []struct {
+		item     string
+		deviceID uint64
+		allowed  bool
+	}{
+		{"/root", 1, true},
+		{"/usr", 1, true},
+
+		{"/proc", 2, false},
+		{"/proc/1234", 2, false},
+
+		{"/usr", 3, false},
+		{"/usr/share", 3, false},
+
+		{"/usr/local", 5, true},
+		{"/usr/local/foobar", 5, true},
+
+		{"/usr/local/foobar/submount", 23, false},
+		{"/usr/local/foobar/submount/file", 23, false},
+
+		{"/usr/local/foobar/outhersubmount", 1, false},
+		{"/usr/local/foobar/outhersubmount/otherfile", 1, false},
+	}
+
+	for _, test := range tests {
+		t.Run("", func(t *testing.T) {
+			res, err := deviceMap.IsAllowed(filepath.FromSlash(test.item), test.deviceID)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if res != test.allowed {
+				t.Fatalf("wrong result returned by IsAllowed(%v): want %v, got %v", test.item, test.allowed, res)
+			}
+		})
+	}
+}