diff --git a/docs/generated_project_py.md b/docs/generated_project_py.md
index 012d988..514299e 100644
--- a/docs/generated_project_py.md
+++ b/docs/generated_project_py.md
@@ -10,6 +10,7 @@ from phmutest.skip import sys_tool as _phm_sys
 
 _phm_globals = None
 _phm_testcase = unittest.TestCase()
+_phm_testcase.maxDiff = None
 _phm_log = []
 
 
diff --git a/docs/generated_share_demo_py.md b/docs/generated_share_demo_py.md
index 61c759d..86ab165 100644
--- a/docs/generated_share_demo_py.md
+++ b/docs/generated_share_demo_py.md
@@ -10,6 +10,7 @@ from phmutest.skip import sys_tool as _phm_sys
 
 _phm_globals = None
 _phm_testcase = unittest.TestCase()
+_phm_testcase.maxDiff = None
 _phm_log = []
 
 
diff --git a/src/phmutest/cases.py b/src/phmutest/cases.py
index 2a2b6d3..1c8a16a 100644
--- a/src/phmutest/cases.py
+++ b/src/phmutest/cases.py
@@ -319,6 +319,7 @@ def markdown_file(
 $callfixture
 _phm_globals = None
 _phm_testcase = unittest.TestCase()
+_phm_testcase.maxDiff = None
 _phm_log = []
 $setupmodule
 $teardownmodule
diff --git a/tests/py/generated_project.py b/tests/py/generated_project.py
index 106060a..d13c277 100644
--- a/tests/py/generated_project.py
+++ b/tests/py/generated_project.py
@@ -7,6 +7,7 @@
 
 _phm_globals = None
 _phm_testcase = unittest.TestCase()
+_phm_testcase.maxDiff = None
 _phm_log = []
 
 
diff --git a/tests/py/generated_sharedemo.py b/tests/py/generated_sharedemo.py
index 92e1480..665ab5e 100644
--- a/tests/py/generated_sharedemo.py
+++ b/tests/py/generated_sharedemo.py
@@ -7,6 +7,7 @@
 
 _phm_globals = None
 _phm_testcase = unittest.TestCase()
+_phm_testcase.maxDiff = None
 _phm_log = []