diff --git a/Makefile b/Makefile
index 7d38355..70efc05 100644
--- a/Makefile
+++ b/Makefile
@@ -5,9 +5,12 @@ TEST_SIM_PKG=https://course.ccs.neu.edu/cs3700sp20/archive/bgp-sim.tar.gz
 
 all:
 
-$(TESTS_DIR):
+$(TESTS_DIR): $(TESTS_DIR)/sim
 	mkdir -p $(TESTS_DIR)
 	sudo ./scripts/nspawn-support.sh create $(TESTS_DIR)/container
+
+$(TESTS_DIR)/sim:
+	mkdir -p $(TESTS_DIR)
 	cd $(TESTS_DIR) && wget -O bgp-sim.tar.gz $(TEST_SIM_PKG)
 	cd $(TESTS_DIR) && tar xf bgp-sim.tar.gz