test(build): a better way to pin light-thread packages

Also, clearly indicate when we are skipping tests because the packages aren't
available.

Author: nedbat

Makefile

@@ -74,6 +74,7 @@ upgrade: 				## update the *.pip files with the latest packages satisfying *.in
 	$(PIP_COMPILE) -o requirements/kit.pip requirements/kit.in
 	$(PIP_COMPILE) -o requirements/tox.pip requirements/tox.in
 	$(PIP_COMPILE) -o requirements/dev.pip requirements/dev.in
+	$(PIP_COMPILE) -o requirements/light-threads.pip requirements/light-threads.in
 	$(PIP_COMPILE) -o doc/requirements.pip doc/requirements.in
 
 # Kitting

requirements/dev.pip

@@ -4,7 +4,7 @@
 #
 #    make upgrade
 #
-astroid==2.8.5
+astroid==2.8.6
     # via pylint
 attrs==21.2.0
     # via
@@ -62,7 +62,7 @@ future==0.18.2
     #   pycontracts
 greenlet==1.1.2
     # via -r requirements/dev.in
-hypothesis==6.25.0
+hypothesis==6.27.1
     # via -r requirements/pytest.pip
 idna==3.3
     # via requests

requirements/light-threads.in

@@ -0,0 +1,9 @@
+# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
+# For details: https://github.com/nedbat/coveragepy/blob/master/NOTICE.txt
+
+-c pins.pip
+
+# The light-threads packages we test against
+
+eventlet
+greenlet

requirements/light-threads.pip

@@ -0,0 +1,16 @@
+#
+# This file is autogenerated by pip-compile with python 3.8
+# To update, run:
+#
+#    make upgrade
+#
+dnspython==2.1.0
+    # via eventlet
+eventlet==0.33.0
+    # via -r requirements/light-threads.in
+greenlet==1.1.2
+    # via
+    #   -r requirements/light-threads.in
+    #   eventlet
+six==1.16.0
+    # via eventlet

requirements/pytest.pip

@@ -18,7 +18,7 @@ flaky==3.7.0
     # via -r requirements/pytest.in
 future==0.18.2
     # via pycontracts
-hypothesis==6.25.0
+hypothesis==6.27.1
     # via -r requirements/pytest.in
 iniconfig==1.1.1
     # via pytest

tests/test_concurrency.py

@@ -222,6 +222,7 @@ def try_some_code(self, code, concurrency, the_module, expected_out=None):
 
         if expected_cant_trace is not None:
             assert out == expected_cant_trace
+            pytest.skip(f"Can't test: {expected_cant_trace}")
         else:
             # We can fully measure the code if we are using the C tracer, which
             # can support all the concurrency, or if we are using threads.

tox.ini

@@ -17,8 +17,7 @@ deps =
     -r requirements/pytest.pip
     # gevent 1.3 causes a failure: https://github.com/nedbat/coveragepy/issues/663
     py{36}: gevent==1.2.2
-    py{36,37,38}: eventlet==0.25.1
-    py{36,37,38}: greenlet==0.4.15
+    py{36,37,38,39,310}: -r requirements/light-threads.pip
 
 # Windows can't update the pip version with pip running, so use Python
 # to install things.