test api: wrapper class for CAS version

Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>

test/functional/api/cas/version.py

@@ -0,0 +1,32 @@
+#
+# Copyright(c) 2019-2020 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause-Clear
+#
+
+import os
+
+from api.cas import git
+from packaging import version
+
+
+class CasVersion(version.Version):
+    def can_be_upgraded(self):
+        return self >= CasVersion("v20.1")
+
+    def __str__(self):
+        return f"v{super().__str__()}"
+
+    def __repr__(self):
+        return str(self)
+
+
+def get_available_cas_versions():
+    release_tags = git.get_release_tags()
+
+    versions = [CasVersion(tag) for tag in release_tags]
+
+    return versions
+
+
+def get_upgradable_cas_versions():
+    return [v for v in get_available_cas_versions() if v.can_be_upgraded()]