diff --git a/Lib/idlelib/idle_test/README.txt b/Lib/idlelib/idle_test/README.txt
index a54e74ddda2170..c4b21f26adf0ec 100644
--- a/Lib/idlelib/idle_test/README.txt
+++ b/Lib/idlelib/idle_test/README.txt
@@ -164,7 +164,7 @@ python -m idlelib.idle_test.htest
 5. Test Coverage
 
 Install the coverage package into your Python 3.6 site-packages
-directory.  (Its exact location depends on the OS). 
+directory.  (Its exact location depends on the OS).
 > python3 -m pip install coverage
 (On Windows, replace 'python3 with 'py -3.6' or perhaps just 'python'.)
 
@@ -215,3 +215,28 @@ rem Above opens new report; htmlcov\index.html displays report index
 ---
 The second parameter was added for tests of module x not named test_x.
 (There were several before modules were renamed, now only one is left.)
+
+
+Coverage on Linux and MacOS
+---------------------------
+
+First, install coverage in virtualenv:
+
+$ cd cpython  # Goto cpython root directory
+$ ./python -m venv venv   # Create venv
+$ source venv/bin/activate
+$ (venv) python -m pip install coverage  # Notice that is using `python`, not `./python`
+
+then, using command line to manipulate like this:
+
+$ (venv) python -m coverage run --source Lib/idlelib Lib/idlelib/idle_test/test_config.py
+$ (venv) python -m coverage report --show-missing
+$ (venv) python -m coverage html
+
+You can replace `test_config.py` to the test you want to mesure, and the source
+argument, you can set to specific file like `Lib/idlelib/config.py`.
+
+If you don't want to do it in virtualenv, you can move coverage from venv to Lib:
+
+$ cp -r venv/lib/python3.7/site-packages/coverage Lib/coverage
+$ ./python -m coverage run --source Lib/idlellib Lib/idlelib/idle_test/test_config.py