update README

README.rst

@@ -52,7 +52,7 @@ Up-to-date documentation is available on `Read the Docs`_.
 Development
 -----------
 
-Please make sure you have Python 3.4+ and `pip-tools`_ installed.
+Please make sure you have Python 3.4+ installed.
 
 1. Git clone the repository -
    :code:`git clone https://github.com/siddhantgoel/streaming-form-data`
@@ -63,6 +63,10 @@ Please make sure you have Python 3.4+ and `pip-tools`_ installed.
 3. That's basically it. You should now be able to run the test suite -
    :code:`py.test`.
 
+Please note that :code:`tests/test_parser_stress.py` stress tests the parser
+with large inputs, which can take a while. As an alternative, pass the filename
+as an argument to :code:`py.test` to run tests selectively.
+
 
 .. _pip tools: https://github.com/jazzband/pip-tools
 .. _Read the Docs: https://streaming-form-data.readthedocs.io/