use --failed-furst for make devtest

requirements/development.txt

@@ -34,3 +34,16 @@ snakeviz
 # add one after you've tested it and found it to be actually useful.
 
 ipython     # nuff said
+
+
+# A command line utility to display dependency tree of the installed Python packages
+# https://github.com/naiquevin/pipdeptree
+#
+# For graph output you will need to:
+# $ sudo apt install -y graphviz
+# $ pipdeptree --graph-output svg > requirements/tree.svg
+pipdeptree
+graphviz
+
+# run failed tests first
+pytest-cache