Change to enable running two unit tests on MacOS (#210)

* Increase sleep time in run_interactive_interrupt and run tests on MacOS

In my testing on MacOS, the "test_interactive_interrupt" test passed without
any changes needed, and the "test_headless_interrupt" test only needed to have
this sleep time increased to pass.

* Use different sleep time in test depending on platform

The previous commit caused a unit test to fail on Linux.  This change fixes
that.

* Increase timeout value passed to find_embedding() call in test

* Raise time threshold for exit condition in unit test

* Skip two unit tests on win32 platform

tests/test_lib.py

@@ -28,7 +28,6 @@
 import signal
 import multiprocessing
 import unittest
-from unittest import SkipTest
 
 # Given that this test is in the tests directory, the calibration data should be
 # in a sub directory. Use the path of this source file to find the calibration
@@ -346,14 +345,6 @@ def check_args(Q, A, initial_chains=None, fixed_chains=None, restrict_chains=Non
                 u, fullset)) & edgelord, "%s and %s are connected as variables but not as domains" % (u, v)
 
 
-def skip_if(cond):
-    if cond:
-        def _skip():
-            raise SkipTest
-        return lambda f: _skip
-    else:
-        return lambda f: f
-
 class TestFindEmbedding(unittest.TestCase):
     @staticmethod
     @success_count(100, 5)
@@ -848,34 +839,13 @@ def test_variable_components_many():
         return find_embedding(K, C, tries=1, chainlength_patience=0)
 
     @staticmethod
-    @skip_if(
-        # there appears to be a bug in the osx, py3.8+ version of multiprocessing.
-        # this has turned into a yak-shaving exercise and I'm not doing any more here
-        # for the time being -- #TODO if anybody has a mac and they wanna dig in, please do
-        (sys.version_info[:2] >= (3, 8) and sys.platform == 'darwin') or
-
-        # TODO this test seems to actually work on windows but it's doing something funky
-        # to our appveyor framework.  Giving up on yak-shaving 'cause we're going to retire
-        # appveyor soon
-        (sys.platform == 'win32')
-    )
-    @staticmethod
+    @unittest.skipIf(sys.platform == 'win32', 'Test may hang on win32, skipping out of caution')
     @success_perfect(1)
     def test_interactive_interrupt():
         return run_interactive_interrupt(True) == 0
 
     @staticmethod
-    @skip_if(
-        # there appears to be a bug in the osx, py3.8+ version of multiprocessing.
-        # this has turned into a yak-shaving exercise and I'm not doing any more here
-        # for the time being -- #TODO if anybody has a mac and they wanna dig in, please do
-        (sys.version_info[:2] >= (3, 8) and sys.platform == 'darwin') or
-
-        # TODO this test seems to actually work on windows but it's doing something funky
-        # to our appveyor framework.  Giving up on yak-shaving 'cause we're going to retire
-        # appveyor soon
-        (sys.platform == 'win32')
-    )
+    @unittest.skipIf(sys.platform == 'win32', 'Test hangs on win32')
     @success_perfect(1)
     def test_headless_interrupt():
         return run_interactive_interrupt(False) == 2
@@ -887,11 +857,11 @@ def _long_running_successful_problem(interactive):
     t0 = time.perf_counter()
     try:
         find_embedding_orig(C, C, chainlength_patience=1 << 20,
-                            interactive=interactive, timeout=1)
+                            interactive=interactive, timeout=2)
     except KeyboardInterrupt:
         sys.exit(2)
-    if time.perf_counter() - t0 > .5:
-        # be a little generous here... but the caller should kill this in way less than .5s
+    if time.perf_counter() - t0 > 1.5:
+        # be a little generous here... but the caller should kill this in way less than 1.5s
         sys.exit(1)
 
 
@@ -904,7 +874,7 @@ def run_interactive_interrupt(interactive):
     p = multiprocessing.Process(
         target=_long_running_successful_problem, args=(interactive,))
     p.start()
-    time.sleep(.1)
+    time.sleep(.1 if sys.platform == 'linux' else 1)
     os.kill(p.pid, ctrl_c)
     p.join()
     # exitcode 0: terminated successfully (interactive mode catches the interrupt)