Separately profile cached and uncached lookup performance.

... in preparation of adding a lookup cache.

Author: anntzer

tox.ini

@@ -38,7 +38,10 @@ use_develop = False
 deps =
 	ipython
 commands =
-	python -m timeit -s 'import importlib_metadata' -- 'importlib_metadata.distribution("ipython")'
+	python -c 'print("Cached lookup performance")'
+	python -m timeit -s 'import importlib_metadata; importlib_metadata.distribution("ipython")' -- 'importlib_metadata.distribution("ipython")'
+	python -c 'print("Uncached lookup performance")'
+	python -m timeit -s 'import importlib, importlib_metadata' -- 'importlib.invalidate_caches(); importlib_metadata.distribution("ipython")'
 
 [testenv:release]
 skip_install = True