diff --git a/MakefileVenv b/MakefileVenv
index 47017b8..518b8a0 100644
--- a/MakefileVenv
+++ b/MakefileVenv
@@ -19,7 +19,7 @@ install:
 	$(python) -m pip install -r requirements.txt
 
 test:
-	$(python) -m unittest --discover .
+	already_in_venv=True $(python) -m unittest discover .
 
 
 run:
diff --git a/test_guidelines.py b/test_guidelines.py
index aef608a..b203c73 100644
--- a/test_guidelines.py
+++ b/test_guidelines.py
@@ -2,8 +2,10 @@
 Testing guidelines and install
 """
 
+import os
+
 import unittest
-from subprocess import run
+from subprocess import run, CalledProcessError
 import pathlib
 
 
@@ -20,8 +22,9 @@ class TestGuidelines(unittest.TestCase):
         target = pathlib.Path(root_dir) / "requirements.txt"
         assert target.exists()
 
-        assert target.isFile()
+        assert target.is_file()
 
+    @unittest.skipIf(os.environ.get("already_in_venv"), "Avoid self call infinite loop")
     def test_environment(self):
         """We want to make sure that the project is virtualenv compatible.
         we may provie and extra makefile for that (and automate build phase)
@@ -33,6 +36,6 @@ class TestGuidelines(unittest.TestCase):
             with self.subTest(setp=step):
                 try:
                     run(["make", *venv, step], check=True)
-                except Exception as E:
+                except CalledProcessError as E:
                     print(E.output)
                     raise