Adapt the garbage collection tests to run under PyPy. This makes the overall...

Adapt the garbage collection tests to run under PyPy. This makes the overall test diff smaller and easier to read.

src/Acquisition/tests.py

@@ -354,6 +354,10 @@ else:
     PY3 = False
 py_impl = getattr(platform, 'python_implementation', lambda: None)
 PYPY = py_impl() == 'PyPy'
+if not hasattr(gc, 'get_threshold'):
+    # PyPy
+    gc.get_threshold = lambda: ()
+    gc.set_threshold = lambda *x: None
 
 import ExtensionClass
 import Acquisition
@@ -1795,10 +1799,10 @@ def showaq(m_self, indent=''):
         rval = rval + indent + id + "\n"
     return rval
 
-if hasattr(gc, 'get_threshold'):
-    #CPython implementation detail
-    def test_Basic_gc():
-        """Test to make sure that EC instances participate in GC
+def test_Basic_gc():
+    """Test to make sure that EC instances participate in GC.
+    Note that PyPy always reports 0 collected objects even
+    though we can see its finalizers run.
 
     >>> from ExtensionClass import Base
     >>> import gc
@@ -1820,7 +1824,7 @@ if hasattr(gc, 'get_threshold'):
     ...     ignore = gc.collect()
     ...     del a
     ...     removed = gc.collect()
-        ...     print(removed > 0)
+    ...     print(removed > 0 or PYPY)
     removed
     True
     removed
@@ -1829,8 +1833,10 @@ if hasattr(gc, 'get_threshold'):
     >>> gc.set_threshold(*thresholds)
 
     """
-    def test_Wrapper_gc():
-        """Test to make sure that EC instances participate in GC
+def test_Wrapper_gc():
+    """Test to make sure that EC instances participate in GC.
+    Note that PyPy always reports 0 collected objects even
+    though we can see its finalizers run.
 
     >>> import gc
     >>> thresholds = gc.get_threshold()
@@ -1848,7 +1854,7 @@ if hasattr(gc, 'get_threshold'):
     ...     ignored = gc.collect()
     ...     del a
     ...     removed = gc.collect()
-        ...     removed > 0
+    ...     removed > 0 or PYPY
     removed
     True
     removed