Makefile adaption for venv usage

scripts/Makefile

-COV2_CMD=python2-coverage
-COV3_CMD=python3-coverage
-PYT2_CMD=python2
-PYT3_CMD=python3
+COV2_CMD=venv2/bin/coverage
+COV3_CMD=venv3/bin/coverage
+PYT2_CMD=venv2/bin/python
+PYT3_CMD=venv3/bin/python
 PDF_CMD=xdg-open
 
 OUTDIR=testresults
 smoke: testrun_smoke finalise compile status
 single: testrun_single finalise compile status
 
-clean:
-	@echo "\033[1;33mCleaning up unittest...\e[0m"
-	@echo "\e[1m  * Testresults from last testrun\e[0m"
+venv:
+	@[[ -d venv2 ]] || make venv2
+	@[[ -d venv3 ]] || make venv3
+
+venv2:
+	virtualenv -p /usr/bin/python2 venv2
+	venv2/bin/pip install --upgrade pip
+	venv2/bin/pip install -r requirements.txt
+venv3:
+	virtualenv -p /usr/bin/python3 venv3
+	venv3/bin/pip install --upgrade pip
+	venv3/bin/pip install -r requirements.txt
+
+clean: venv
+	@echo -e "\033[1;33mCleaning up unittest...\e[0m"
+	@echo -e "\e[1m  * Testresults from last testrun\e[0m"
 	@ls testresults | xargs -i echo "    testresults/{}"
 	@ls testresults | xargs -i rm -f "testresults/{}"
-	@echo "\e[1m  * Collected coverage information\e[0m"
+	@echo -e "\e[1m  * Collected coverage information\e[0m"
 	@$(COV3_CMD) erase
 
+cleanall: clean
+	@echo -e "\e[1m  * Virtualenv\e[0m"
+	@rm -rf venv?
+
 release_testcases:
 	@$(PYT3_CMD) src/unittest/scripts/unittest.py release_testcases
 
-prepare:
+prepare: venv
 	@$(PYT3_CMD) src/unittest/scripts/unittest.py prepare
 
 testrun_full: clean prepare