Index: Lib/importlib/test/source/test_abc_loader.py
===================================================================
--- Lib/importlib/test/source/test_abc_loader.py	(revision 72524)
+++ Lib/importlib/test/source/test_abc_loader.py	(working copy)
@@ -157,10 +157,10 @@
         mock = self.mocker({name: path})
         with util.uncache(name):
             module = mock.load_module(name)
-            self.assert_(name in sys.modules)
+            self.assertIn(name, sys.modules)
         self.eq_attrs(module, __name__=name, __file__=path, __package__='pkg',
                         __loader__=mock)
-        self.assert_(not hasattr(module, '__path__'))
+        self.assertFalse(hasattr(module, '__path__'))
         return mock, name
 
     def test_module_reuse(self):
@@ -247,17 +247,17 @@
 
     mocker = PyPycLoaderMock
 
-    @source_util.writes_bytecode
+    @source_util.writes_bytecode_files
     def verify_bytecode(self, mock, name):
         assert name in mock.module_paths
-        self.assert_(name in mock.module_bytecode)
+        self.assertIn(name, mock.module_bytecode)
         magic = mock.module_bytecode[name][:4]
         self.assertEqual(magic, imp.get_magic())
         mtime = importlib._r_long(mock.module_bytecode[name][4:8])
         self.assertEqual(mtime, 1)
         bc = mock.module_bytecode[name][8:]
+        self.assertEqual(bc, mock.compile_bc(name))
 
-
     def test_module(self):
         mock, name = super().test_module()
         self.verify_bytecode(mock, name)
@@ -286,7 +286,7 @@
     """Test that bytecode is properly handled based on
     sys.dont_write_bytecode."""
 
-    @source_util.writes_bytecode
+    @source_util.writes_bytecode_files
     def run_test(self, dont_write_bytecode):
         name = 'mod'
         mock = PyPycLoaderMock({name: os.path.join('path', 'to', 'mod')})
@@ -307,7 +307,7 @@
 
     """Test that bytecode is regenerated as expected."""
 
-    @source_util.writes_bytecode
+    @source_util.writes_bytecode_files
     def test_different_magic(self):
         # A different magic number should lead to new bytecode.
         name = 'mod'
@@ -323,7 +323,7 @@
         magic = mock.module_bytecode[name][:4]
         self.assertEqual(magic, imp.get_magic())
 
-    @source_util.writes_bytecode
+    @source_util.writes_bytecode_files
     def test_old_mtime(self):
         # Bytecode with an older mtime should be regenerated.
         name = 'mod'
Index: Lib/importlib/test/source/util.py
===================================================================
--- Lib/importlib/test/source/util.py	(revision 72524)
+++ Lib/importlib/test/source/util.py	(working copy)
@@ -9,32 +9,23 @@
 from test import support
 
 
-def writes_bytecode(fxn):
-    """Decorator to protect sys.dont_write_bytecode from mutation."""
+def writes_bytecode_files(fxn):
+    """Decorator to protect sys.dont_write_bytecode from mutation and to skip
+    tests that require it to be set to False."""
+    if sys.dont_write_bytecode:
+        return lambda *args, **kwargs: None
     @functools.wraps(fxn)
     def wrapper(*args, **kwargs):
         original = sys.dont_write_bytecode
         sys.dont_write_bytecode = False
-        to_return = fxn(*args, **kwargs)
-        sys.dont_write_bytecode = original
+        try:
+            to_return = fxn(*args, **kwargs)
+        finally:
+            sys.dont_write_bytecode = original
         return to_return
     return wrapper
 
 
-def writes_bytecode_files(fxn):
-    """Decorator that returns the function if writing bytecode is enabled, else
-    a stub function that accepts anything and simply returns None."""
-    if sys.dont_write_bytecode:
-        return lambda *args, **kwargs: None
-    else:
-        @functools.wraps(fxn)
-        def wrapper(*args, **kwargs):
-            to_return = fxn(*args, **kwargs)
-            sys.dont_write_bytecode = False
-            return to_return
-        return wrapper
-
-
 def bytecode_path(source_path):
     for suffix, _, type_ in imp.get_suffixes():
         if type_ == imp.PY_COMPILED: