diff --git a/Makefile b/Makefile
index 926d6ca..d6e1172 100644
--- a/Makefile
+++ b/Makefile
@@ -12,22 +12,24 @@ SHELL := bash
 .SHELLFLAGS := -eu -o pipefail -c
 
 .PHONY: all
-all:
-	sudo python3 -m pip install --upgrade --force-reinstall .
+all: install
 
-# Python Dependency Locking with pip-tools
-# https://lincolnloop.com/insights/python-dependency-locking-pip-tools/
+.PHONY: install
+install:
+	sudo python3 -m pip install --upgrade --force-reinstall .
 
 .PHONY: test
 test: venv
 	source venv/bin/activate
+	export PYTHONPATH="${PYTHONPATH}:src"
+
 	python3 src/subprocess_util/test.py
 
+.PHONY: venv
 venv:
-	if [ -d venv ]; then
-	  rm -r venv
+	if [ ! -d venv ]; then
+	  	python3 -m venv venv
 	fi
-	python3 -m venv venv
 
 .PHONY: clean
 clean: