Add a hacking rule for deprecated assertion methods

Add a hacking rule for the following deprecated methods(*)
in Python 3.

* assertRegexpMatches
* assertNotRegexpMatches

[N361] assertRegex/assertNotRegex must be used instead of
       assertRegexpMatches/assertNotRegexpMatches.

*: https://docs.python.org/3.6/library/unittest.html#deprecated-aliases

Change-Id: Icfbaf26a7db6986820e264d1888982b985d613a1

HACKING.rst

@@ -68,6 +68,8 @@ Nova Specific Commandments
 - [N358] Return must always be followed by a space when returning a value.
 - [N359] Check for redundant import aliases.
 - [N360] Yield must always be followed by a space when yielding a value.
+- [N361] Check for usage of deprecated assertRegexpMatches and
+  assertNotRegexpMatches
 
 Creating Unit Tests
 -------------------

nova/hacking/checks.py

@@ -100,6 +100,8 @@ return_not_followed_by_space = re.compile(r"^\s*return(?:\(|{|\"|'|#).*$")
 uuid4_re = re.compile(r"uuid4\(\)($|[^\.]|\.hex)")
 redundant_import_alias_re = re.compile(r"import (?:.*\.)?(.+) as \1$")
 yield_not_followed_by_space = re.compile(r"^\s*yield(?:\(|{|\[|\"|').*$")
+asse_regexpmatches = re.compile(
+    r"(assertRegexpMatches|assertNotRegexpMatches)\(")
 
 
 class BaseASTChecker(ast.NodeVisitor):
@@ -838,6 +840,17 @@ def yield_followed_by_space(logical_line):
                "N360: Yield keyword should be followed by a space.")
 
 
+def assert_regexpmatches(logical_line):
+    """Check for usage of deprecated assertRegexpMatches/assertNotRegexpMatches
+
+    N361
+    """
+    res = asse_regexpmatches.search(logical_line)
+    if res:
+        yield (0, "N361: assertRegex/assertNotRegex must be used instead "
+                  "of assertRegexpMatches/assertNotRegexpMatches.")
+
+
 def factory(register):
     register(import_no_db_in_virt)
     register(no_db_session_in_public_api)
@@ -881,3 +894,4 @@ def factory(register):
     register(return_followed_by_space)
     register(no_redundant_import_alias)
     register(yield_followed_by_space)
+    register(assert_regexpmatches)

nova/tests/unit/test_hacking.py

@@ -839,3 +839,17 @@ class HackingTestCase(test.NoDBTestCase):
                   yieldx_func(a, b)
                """
         self._assert_has_no_errors(code, checks.yield_followed_by_space)
+
+    def test_assert_regexpmatches(self):
+        code = """
+                   self.assertRegexpMatches("Test", output)
+                   self.assertNotRegexpMatches("Notmatch", output)
+               """
+        errors = [(x + 1, 0, 'N361') for x in range(2)]
+        self._assert_has_errors(code, checks.assert_regexpmatches,
+                                expected_errors=errors)
+        code = """
+                   self.assertRegexpMatchesfoo("Test", output)
+                   self.assertNotRegexpMatchesbar("Notmatch", output)
+               """
+        self._assert_has_no_errors(code, checks.assert_regexpmatches)