change python README.txt

python/README.txt

@@ -46,8 +46,10 @@ Installation
 4) Build and run the tests:
 
      $ python setup.py build
-     $ python setup.py test
-     $ python setup.py exttest  # To test C++ implementation (see below).
+     $ python setup.py google_test
+     
+     if you want to test c++ implementation, run:
+     $ python setup.py google_test --cpp_implementation
 
    If some tests fail, this library may not work correctly on your
    system.  Continue at your own risk.
@@ -63,6 +65,8 @@ Installation
 5) Install:
 
      $ python setup.py install
+     or:
+     $ python setup.py install --cpp_implementation
 
    This step may require superuser privileges.
    NOTE: To use C++ implementation, you need to install C++ protobuf runtime
@@ -97,7 +101,8 @@ You need to export this variable before running setup.py script to build and
 install the extension.  You must also set the variable at runtime, otherwise
 the pure-Python implementation will be used. In a future release, we will
 change the default so that C++ implementation is used whenever it is available.
-It is strongly recommended to run `python setup.py test` after setting the
+It is strongly recommended to run `python setup.py google_test
+--cpp_implementation` after setting the
 variable to "cpp", so the tests will be against C++ implemented Python
 messages.