Deprecate recursionlimit kwarg to matplotlib.test().

It was added in c013ed7 to apparently fix a failure on OSX/Py36, but in
fact it's been unused ever since
MacPython/matplotlib-wheels@90a94c0
(merely a month later), and tests apparently still pass fine.

Author: anntzer

doc/api/next_api_changes/deprecations.rst

@@ -232,3 +232,7 @@ Axes navigation can still be toggled programmatically using
 The following related APIs are also deprecated:
 ``backend_tools.ToolEnableAllNavigation``,
 ``backend_tools.ToolEnableNavigation``, and ``rcParams["keymap.all_axes"]``.
+
+``matplotlib.test(recursionlimit=...)``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The *recursionlimit* parameter of ``matplotlib.test`` is deprecated.

lib/matplotlib/__init__.py

@@ -1177,6 +1177,7 @@ def _init_tests():
 
 
 @cbook._delete_parameter("3.2", "switch_backend_warn")
+@cbook._delete_parameter("3.3", "recursionlimit")
 def test(verbosity=None, coverage=False, switch_backend_warn=True,
          recursionlimit=0, **kwargs):
     """Run the matplotlib test suite."""

tests.py

@@ -39,11 +39,14 @@
     from matplotlib import test
 
     parser = argparse.ArgumentParser(add_help=False)
-    parser.add_argument('--recursionlimit', type=int, default=0,
+    parser.add_argument('--recursionlimit', type=int, default=None,
                         help='Specify recursionlimit for test run')
     args, extra_args = parser.parse_known_args()
 
     print('Python byte-compilation optimization level:', sys.flags.optimize)
 
-    retcode = test(argv=extra_args, recursionlimit=args.recursionlimit)
+    if args.recursionlimit is not None:  # Will trigger deprecation.
+        retcode = test(argv=extra_args, recursionlimit=args.recursionlimit)
+    else:
+        retcode = test(argv=extra_args)
     sys.exit(retcode)