tests: Update tests scripts.

tests.sh

@@ -1,12 +1,15 @@
 #! /bin/sh
 
-echo " Setup ENV"
+if [ -z "$GUIX_ENVIRONMENT" ]
+then
+    echo " Setup ENV"
 
-python3 -m venv venv
+    python3 -m venv venv
-. venv/bin/activate
+    . venv/bin/activate
-pip3 install -U pip
+    pip3 install -U pip
-pip3 install -r ./full-requirements.txt
+    pip3 install -r ./full-requirements.txt
-pip3 install -U -r ./full-requirements.txt
+    pip3 install -U -r ./full-requirements.txt
+fi
 
 echo " UNITTEST"