Add version compare function

Add version compare function for xcat and requested version
so, functions not supported by future release of xcat
will use old version interface.

Change-Id: I22927e7aad338b11f850787d87ea2f211c90dd28

nova/tests/unit/virt/zvm/test_zvm.py

@@ -1590,6 +1590,26 @@ class ZVMDriverTestCases(ZVMTestCase):
         version = self.driver._get_xcat_version()
         self.assertEqual(version, 2008003005)
 
+    @mock.patch('nova.virt.zvm.driver.ZVMDriver._get_xcat_version')
+    def test_has_min_version(self, fake_xcat_ver):
+        fake_xcat_ver.return_value = 1002003004
+
+        self.assertFalse(self.driver.has_min_version((1, 3, 3, 4)))
+        self.assertTrue(self.driver.has_min_version((1, 1, 3, 5)))
+        self.assertTrue(self.driver.has_min_version(None))
+
+    @mock.patch('nova.virt.zvm.driver.ZVMDriver._get_xcat_version')
+    def test_has_version(self, fake_xcat_ver):
+        fake_xcat_ver.return_value = 1002003004
+
+        xcat_ver = (1, 2, 3, 4)
+        self.assertTrue(self.driver.has_version(xcat_ver))
+
+        for xcat_ver_ in [(1, 1, 3, 4), (1, 3, 3, 2)]:
+            self.assertFalse(self.driver.has_version(xcat_ver_))
+
+        self.assertTrue(self.driver.has_version(None))
+
 
 class ZVMInstanceTestCases(ZVMTestCase):
     """Test cases for zvm.instance."""

nova/virt/zvm/driver.py

@@ -14,6 +14,7 @@
 
 import contextlib
 import datetime
+import operator
 import os
 import time
 import uuid
@@ -2000,3 +2001,19 @@ class ZVMDriver(driver.ComputeDriver):
             version = dict_str.split()[1]
             version = versionutils.convert_version_to_int(version)
         return version
+
+    def _version_check(self, req_ver=None, op=operator.lt):
+        try:
+            if req_ver is not None:
+                cur_ver = self._get_xcat_version()
+                if op(cur_ver, versionutils.convert_version_to_int(req_ver)):
+                    return False
+            return True
+        except Exception:
+            return False
+
+    def has_min_version(self, req_ver=None):
+        return self._version_check(req_ver=req_ver, op=operator.lt)
+
+    def has_version(self, req_ver=None):
+        return self._version_check(req_ver=req_ver, op=operator.ne)