diff --git a/doc/source/ch06_unittest.rst b/doc/source/ch06_unittest.rst
index e2cfdc442572ec003e760128d9c36262c684dfbb..b7f4c18f2ce8b5ff5a8b1357d6e3f5fcb478c232 100644
--- a/doc/source/ch06_unittest.rst
+++ b/doc/source/ch06_unittest.rst
@@ -36,7 +36,7 @@ To run unit tests collected from directory ``.``, and calculate coverage for sou
 
 You will see messages like below
 
-.. code-block:: plain
+.. code-block:: none
 
     ============================ test session starts ============================
     platform darwin -- Python 3.9.7, pytest-7.1.3, pluggy-0.13.1
diff --git a/doc/source/ch09_build.rst b/doc/source/ch09_build.rst
index 9282a6556f25f49ac40e289d890e9cf6957b8001..99a08802e48fbb04399f0081867ea0f0da81bc33 100644
--- a/doc/source/ch09_build.rst
+++ b/doc/source/ch09_build.rst
@@ -67,7 +67,7 @@ The build log includes 6 sections.
 An example of test summary is at the end of build log (the attached ``build.zip``).
 If all checks/tests/validations passed, you will see a section as below.
 
-.. code-block:: plain
+.. code-block:: none
 
     ===================== TEST SUMMARY =====================
     Test passed!
@@ -85,7 +85,7 @@ Unit test coverage report
 The ``build log`` also contains a section of unit test coverage report.
 An example is below.
 
-.. code-block:: plain
+.. code-block:: none
 
     ---------- coverage: platform darwin, python 3.9.7-final-0 -----------
     Name                                Stmts   Miss  Cover   Missing