fix python2.5 compatibility

CHANGELOG

@@ -1,6 +1,7 @@
 Changes between 2.0.3 and 2.1.0.DEV
 ----------------------------------------------
 
+- fix issue58 and issue59: new assertion code fixes
 - merge Benjamin's assertionrewrite branch: now assertions
   for test modules on python 2.6 and above are done by rewriting
   the AST and saving the pyc file before the test module is imported.

_pytest/__init__.py

@@ -1,2 +1,2 @@
 #
-__version__ = '2.1.0.dev4'
+__version__ = '2.1.0.dev5'

_pytest/assertion/__init__.py

@@ -7,8 +7,6 @@ import pytest
 from _pytest.monkeypatch import monkeypatch
 from _pytest.assertion import util
 
-REWRITING_AVAILABLE = "_ast" in sys.builtin_module_names
-
 def pytest_addoption(parser):
     group = parser.getgroup("debugconfig")
     group.addoption('--assertmode', action="store", dest="assertmode",
@@ -40,7 +38,10 @@ def pytest_configure(config):
         mode = "off"
     elif mode == "default":
         mode = "rewrite"
-    if mode == "on" and not REWRITING_AVAILABLE:
+    if mode == "rewrite":
+        try:
+            import ast
+        except ImportError:
             mode = "reinterp"
     if mode != "off":
         _load_modules(mode)

setup.py

@@ -22,7 +22,7 @@ def main():
         name='pytest',
         description='py.test: simple powerful testing with Python',
         long_description = long_description,
-        version='2.1.0.dev4',
+        version='2.1.0.dev5',
         url='http://pytest.org',
         license='MIT license',
         platforms=['unix', 'linux', 'osx', 'cygwin', 'win32'],

testing/test_assertion.py

@@ -120,6 +120,7 @@ class TestAssert_reprcompare:
         expl = ' '.join(callequal('foo', 'bar'))
         assert 'raised in repr()' not in expl
 
+@needsnewassert
 def test_rewritten(testdir):
     testdir.makepyfile("""
         def test_rewritten():