make genscript provide information as to compatibility

(now that argparse is a dependency on python2.6)

CHANGELOG

@@ -1,9 +1,12 @@
 Changes between 2.3.5 and 2.4.DEV
 -----------------------------------
 
-- integrate option tab-completion when argcomplete is used.  Thanks
-  Anthon van der Neut for the PR.  This also lets pytest use argparse
-  instead of optparse.
+- integrate tab-completion on options through use of "argcomplete".
+  Thanks Anthon van der Neut for the PR.
+
+- pytest now uses argparse instead of optparse (thanks Anthon) which 
+  means that "argparse" is added as a dependency if installing into python2.6
+  environments or below.
 
 - SO-17664702: call fixture finalizers even if the fixture function
   partially failed (finalizers would not always be called before)
@@ -68,6 +71,13 @@ Changes between 2.3.5 and 2.4.DEV
 
 - better parametrize error messages, thanks Brianna Laugher
 
+known incompatibilities:
+
+- if calling --genscript from python2.7 or above, you only get a
+  standalone script which works on python2.7 or above.  Use Python2.6
+  to also get a python2.5 compatible version.
+
+
 Changes between 2.3.4 and 2.3.5
 -----------------------------------
 

_pytest/genscript.py

@@ -1,5 +1,6 @@
 """ generate a single-file self-contained version of py.test """
 import py
+import sys
 
 def find_toplevel(name):
     for syspath in py.std.sys.path:
@@ -59,11 +60,21 @@ def pytest_addoption(parser):
 def pytest_cmdline_main(config):
     genscript = config.getvalue("genscript")
     if genscript:
+        tw = py.io.TerminalWriter()
+        deps =  ['py', '_pytest', 'pytest']
+        if sys.version_info < (2,7):
+            deps.append("argparse")
+            tw.line("generated script will run on python2.5-python3.3++")
+        else:
+            tw.line("WARNING: generated script will not run on python2.6 "
+                    "or below due to 'argparse' dependency. Use python2.6 "
+                    "to generate a python2.5/6 compatible script", red=True)
         script = generate_script(
             'import py; raise SystemExit(py.test.cmdline.main())',
-            ['py', '_pytest', 'pytest'],
+            deps,
         )
-
         genscript = py.path.local(genscript)
         genscript.write(script)
+        tw.line("generated pytest standalone script: %s" % genscript,
+                bold=True)
         return 0

_pytest/standalonetemplate.py

@@ -13,6 +13,10 @@ class DictImporter(object):
         self.sources = sources
 
     def find_module(self, fullname, path=None):
+        if fullname == "argparse" and sys.version_info >= (2,7):
+            # we were generated with <python2.7 (which pulls in argparse)
+            # but we are running now on a stdlib which has it, so use that.
+            return None
         if fullname in self.sources:
             return self
         if fullname + '.__init__' in self.sources:

setup.py

@@ -8,6 +8,10 @@ except ImportError:
 
 long_description = open("README.rst").read()
 def main():
+    install_requires = ["py>=1.4.15"]
+    if sys.version_info < (2,7):
+        install_requires.append("argparse")
+
     setup(
         name='pytest',
         description='py.test: simple powerful testing with Python',
@@ -21,7 +25,7 @@ def main():
         entry_points= make_entry_points(),
         cmdclass = {'test': PyTest},
         # the following should be enabled for release
-        install_requires=['py>=1.4.14'],
+        install_requires=install_requires,
         classifiers=['Development Status :: 6 - Mature',
                      'Intended Audience :: Developers',
                      'License :: OSI Approved :: MIT License',

testing/conftest.py

@@ -77,6 +77,9 @@ winpymap = {
     'python2.5': r'C:\Python25\python.exe',
     'python2.4': r'C:\Python24\python.exe',
     'python3.1': r'C:\Python31\python.exe',
+    'python3.2': r'C:\Python32\python.exe',
+    'python3.3': r'C:\Python33\python.exe',
+    'python3.4': r'C:\Python34\python.exe',
 }
 
 def getexecutable(name, cache={}):

testing/test_genscript.py

@@ -1,10 +1,11 @@
+import pytest
 import py, os, sys
 import subprocess
 
 
-def pytest_funcarg__standalone(request):
-    return request.cached_setup(scope="module",
-        setup=lambda: Standalone(request))
+@pytest.fixture(scope="module")
+def standalone(request):
+    return Standalone(request)
 
 class Standalone:
     def __init__(self, request):
@@ -20,6 +21,12 @@ class Standalone:
         return testdir._run(anypython, self.script, *args)
 
 def test_gen(testdir, anypython, standalone):
+    if sys.version_info >= (2,7):
+        result = testdir._run(anypython, "-c",
+                                "import sys;print sys.version_info >=(2,7)")
+        if result.stdout.str() == "False":
+            pytest.skip("genscript called from python2.7 cannot work "
+                        "earlier python versions")
     result = standalone.run(anypython, testdir, '--version')
     assert result.ret == 0
     result.stderr.fnmatch_lines([

testing/test_parseopt.py

@@ -1,3 +1,4 @@
+from __future__ import with_statement
 import py, pytest
 from _pytest import config as parseopt
 from textwrap import dedent
@@ -44,7 +45,7 @@ class TestParser:
         res = argument.attrs()
         assert res['default'] == 42
         assert res['dest'] == 'abc'
-                    
+
     def test_group_add_and_get(self):
         parser = parseopt.Parser()
         group = parser.getgroup("hello", description="desc")
@@ -128,7 +129,7 @@ class TestParser:
         x = parser.addoption("--ultimate-answer", type=int)
         args = parser.parse(['--ultimate-answer', '42'])
         assert args.ultimate_answer == 42
-        
+
     def test_parse_defaultgetter(self):
         def defaultget(option):
             if not hasattr(option, 'type'):