Update README about running unit tests

Author: Lorak-mmk

README-dev.rst

@@ -95,11 +95,13 @@ Running Unit Tests
 ------------------
 Unit tests can be run like so::
 
-    nosetests -w tests/unit/
+    python -m pytest --import-mode append tests/unit -k 'not (test_connection_initialization or test_cloud)'
+    EVENT_LOOP_MANAGER=gevent python -m pytest --import-mode append tests/unit/io/test_geventreactor.py
+    EVENT_LOOP_MANAGER=eventlet python -m pytest --import-mode append tests/unit/io/test_eventletreactor.py
 
 You can run a specific test method like so::
 
-    nosetests -w tests/unit/test_connection.py:ConnectionTest.test_bad_protocol_version
+    python -m pytest tests/unit/test_connection.py::ConnectionTest::test_bad_protocol_version
 
 Running Integration Tests
 -------------------------
@@ -128,11 +130,11 @@ Seeing Test Logs in Real Time
 -----------------------------
 Sometimes it's useful to output logs for the tests as they run::
 
-    nosetests -w tests/unit/ --nocapture --nologcapture
+    python -m pytest -s tests/unit/
 
 Use tee to capture logs and see them on your terminal::
 
-    nosetests -w tests/unit/ --nocapture --nologcapture 2>&1 | tee test.log
+    python -m pytest -s tests/unit/ 2>&1 | tee test.log
 
 Testing Multiple Python Versions
 --------------------------------