diff --git a/owncloudComLibrary/src/release/java/com/owncloud/android/lib/testing/OpenForTesting.kt b/owncloudComLibrary/src/release/java/com/owncloud/android/lib/testing/OpenForTesting.kt
new file mode 100644
index 00000000..3c91e836
--- /dev/null
+++ b/owncloudComLibrary/src/release/java/com/owncloud/android/lib/testing/OpenForTesting.kt
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.owncloud.android.lib.testing
+
+/**
+ * This annotation allows us to open some classes for mocking purposes while they are final in
+ * release builds.
+ */
+@Target(AnnotationTarget.ANNOTATION_CLASS)
+annotation class OpenClass
+
+/**
+ * Annotate a class with [OpenForTesting] if you want it to be extendable in debug builds.
+ */
+@OpenClass
+@Target(AnnotationTarget.CLASS)
+annotation class OpenForTesting