add a --version option to print the pylib version

--HG--
branch : 1.0.x

CHANGELOG

@@ -11,14 +11,16 @@ Changes between 1.0.0 and 1.0.1
   was adapted and somewhat unified between windows and linux 
 
 * fix issue #27: better reporting on non-collectable items given on commandline 
-  (e.g. pyc files) 
+  (e.g. pyc files)
+
+* fix issue #33: added --version flag (thanks Benjamin Peterson) 
 
 * "Test" prefixed classes are *not* collected by default anymore if they 
   have an __init__ method 
 
 * monkeypatch setenv() now accepts a "prepend" parameter
 
-* terser reporting of collection error tracebacks
+* improved reporting of collection error tracebacks
 
 * simplified multicall mechanism and plugin architecture, 
   renamed some internal methods and argnames 

py/test/plugin/pytest_default.py

@@ -1,5 +1,6 @@
 """ default hooks and general py.test options. """ 
 
+import sys
 import py
 
 def pytest_pyfunc_call(__multicall__, pyfuncitem):
@@ -90,10 +91,17 @@ def pytest_addoption(parser):
                help="shortcut for '--dist=load --tx=NUM*popen'")
     group.addoption('--rsyncdir', action="append", default=[], metavar="dir1", 
                help="add directory for rsyncing to remote tx nodes.")
+    group.addoption('--version', action="store_true",
+                    help="display version information")
 
 def pytest_configure(config):
     fixoptions(config)
     setsession(config)
+    if config.option.version:
+        p = py.path.local(py.__file__).dirpath()
+        print "This is py.test version %s, imported from %s" % (
+            py.__version__, p)
+        sys.exit(0)
     #xxxloadplugins(config)
 
 def fixoptions(config):

py/test/testing/acceptance_test.py

@@ -3,6 +3,14 @@ import py
 EXPECTTIMEOUT=10.0
 
 class TestGeneralUsage:
+    def test_version(self, testdir):
+        assert py.version == py.__version__ 
+        result = testdir.runpytest("--version")
+        assert result.ret == 0
+        p = py.path.local(py.__file__).dirpath()
+        assert result.stderr.fnmatch_lines([
+            '*py.test*%s*, imported from: %s*' % (py.version, p)
+        ])
     def test_config_error(self, testdir):
         testdir.makeconftest("""
             def pytest_configure(config):