Add check for deprecated method assert_

The proper one is assertTrue, assert_ is deprecated as of 2.7.

There were some projects using assert_().
https://review.openstack.org/#/c/44456/

This patch will prevent code from deteriorating.

Change-Id: Id6f0ed85eb62d6ea9a1f352427882743cc3a7101

hacking/core.py

@@ -687,6 +687,22 @@ def hacking_no_assert_equals(logical_line, tokens):
                 "H602: assertEquals is deprecated, use assertEqual")
 
 
+@flake8ext
+def hacking_no_assert_underscore(logical_line, tokens):
+    r"""assert_() is deprecated, use assertTrue instead.
+
+    Okay: self.assertTrue(foo)
+    H603: self.assert_(foo)
+    """
+
+    for token_type, text, start_index, _, _ in tokens:
+
+        if token_type == tokenize.NAME and text == "assert_":
+            yield (
+                start_index[1],
+                "H603: assert_ is deprecated, use assertTrue")
+
+
 FORMAT_RE = re.compile("%(?:"
                        "%|"           # Ignore plain percents
                        "(\(\w+\))?"   # mapping key

setup.cfg

@@ -40,6 +40,7 @@ flake8.extension =
     H501 = hacking.core:hacking_no_locals
     H601 = hacking.core:hacking_no_cr
     H602 = hacking.core:hacking_no_assert_equals
+    H603 = hacking.core:hacking_no_assert_underscore
     H700 = hacking.core:hacking_localization_strings
     H801 = hacking.core:OnceGitCheckCommitTitleBug
     H802 = hacking.core:OnceGitCheckCommitTitleLength