adding a test and some support code for creating

an "sdist" package, unpacking in a virtualenv and
importing and verifying the version

--HG--
branch : 1.0.x

py/test/testing/test_install.py

@@ -0,0 +1,9 @@
+import py
+
+def test_make_sdist_and_run_it(py_setup, venv):
+    sdist = py_setup.make_sdist(venv.path)
+    venv.easy_install(str(sdist)) 
+    gw = venv.makegateway()
+    ch = gw.remote_exec("import py ; channel.send(py.__version__)")
+    version = ch.receive()
+    assert version == py.__version__