Add a testcase to test whether using log.warn

Change-Id: I38ff5865991ceab80f98b4c10c40cffaae5a6946

HACKING.rst

@@ -21,3 +21,4 @@ Zun Specific Commandments
   with a sequence of key-value pairs.
 - [Z338] Use assertIn/NotIn(A, B) rather than assertEqual(A in B, True/False).
 - [Z339] Don't use xrange()
+- [Z352] LOG.warn is deprecated. Enforce use of LOG.warning.

zun/hacking/checks.py

@@ -144,6 +144,20 @@ def dict_constructor_with_list_copy(logical_line):
         yield (0, msg)
 
 
+def no_log_warn(logical_line):
+    """Disallow 'LOG.warn('
+
+    Deprecated LOG.warn(), instead use LOG.warning
+    https://review.openstack.org/#/c/412768/
+
+    Z352
+    """
+
+    msg = ("Z352: LOG.warn is deprecated, please use LOG.warning!")
+    if "LOG.warn(" in logical_line:
+        yield (0, msg)
+
+
 def factory(register):
     register(no_mutable_default_args)
     register(assert_equal_none)
@@ -154,3 +168,4 @@ def factory(register):
     register(use_timeutils_utcnow)
     register(dict_constructor_with_list_copy)
     register(no_xrange)
+    register(no_log_warn)

zun/tests/unit/test_hacking.py

@@ -232,3 +232,16 @@ class HackingTestCase(base.BaseTestCase):
 
         self.assertEqual(0, len(list(checks.dict_constructor_with_list_copy(
             "      self._render_dict(xml, data_el, data.__dict__)"))))
+
+    def test_no_log_warn(self):
+        errors = [(1, 0, "Z352")]
+        check = checks.no_log_warn
+        code = """
+                  LOG.warn("LOG.warn is deprecated")
+               """
+        self._assert_has_errors(code, check, errors)
+
+        code = """
+                  LOG.warning("LOG.warn is deprecated")
+               """
+        self._assert_has_no_errors(code, check)