diff --git a/dockertest/Makefile b/dockertest/Makefile
index c166eea11aa..694e8e49126 100644
--- a/dockertest/Makefile
+++ b/dockertest/Makefile
@@ -1,13 +1,8 @@
 RANDOMSRC = Godeps/_workspace/src/github.com/jbenet/go-random/random
-IPFS_DOCKER_IMAGE = zaqwsx_ipfs-test-img
+IMAGE_NAME = ipfs-test-latest
 
 test: clean setup
-	fig build --no-cache
-	fig up --no-color | tee build/fig.log
-	make save_logs # save the ipfs logs for inspection
-	# fig up won't report the error using an error code, so we grep the
-	# fig.log file to find out whether the call succeeded
-	tail build/fig.log | grep "exited with code 0"
+	./run-test-on-img.sh $(IMAGE_NAME)
 
 setup: docker_ipfs_image data/filetiny data/filerand
 
@@ -23,15 +18,11 @@ data/filerand: bin/random
 bin/random:
 	go build -o ./bin/random ../$(RANDOMSRC)
 
-docker_ipfs_image: build/.built_img
-	docker images | grep $(IPFS_DOCKER_IMAGE)
-
-# this is here so that "make clean; make" rebuilds the docker img.
-# but otherwise will reuse whatever you last built.
-# TODO: make this detect whether code has been changed
-build/.built_img:
-	cd .. && docker build -t $(IPFS_DOCKER_IMAGE) .
-	touch build/.built_img
+# just build it every time... this part isn't
+# even the lengthy part, and it decreases pain.
+docker_ipfs_image:
+	cd .. && docker build -t $(IMAGE_NAME) .
+	docker images | grep $(IMAGE_NAME)
 
 clean:
 	sh bin/clean.sh
@@ -41,4 +32,3 @@ clean:
 	rm -f data/filetiny
 	rm -f data/filerand
 	rm -rf build/*
-	rm -rf build/.built_img
diff --git a/dockertest/run-test-on-img.sh b/dockertest/run-test-on-img.sh
new file mode 100755
index 00000000000..d53cde34b23
--- /dev/null
+++ b/dockertest/run-test-on-img.sh
@@ -0,0 +1,33 @@
+#!/bin/sh
+if [ "$#" -ne 1 ]; then
+  echo "usage: $0 <docker-image-ref>"
+  echo "runs this test on image matching <docker-image-ref>"
+  exit 1
+fi
+
+# this tag is used by the dockerfiles in
+# {data, server, client, bootstrap}
+tag=zaqwsx_ipfs-test-img
+
+# could use set -v, but i dont want to see the comments...
+
+img=$(docker images | grep $1 | awk '{print $3}')
+echo "using docker image: $img ($1)"
+
+echo docker tag -f $img $tag
+docker tag -f $img $tag
+
+echo "fig build --no-cache"
+fig build --no-cache
+
+echo "fig up --no-color | tee build/fig.log"
+fig up --no-color | tee build/fig.log
+
+# save the ipfs logs for inspection
+echo "make save_logs"
+make save_logs
+
+# fig up won't report the error using an error code, so we grep the
+# fig.log file to find out whether the call succeeded
+echo 'tail build/fig.log | grep "exited with code 0"'
+tail build/fig.log | grep "exited with code 0"