Some test code cleanup for #1586

Author: sampsyo

test/test_query.py

@@ -509,35 +509,39 @@ def test_case_sensitivity(self):
         self.assert_items_matched(results, ['path item', 'caps path'])
 
         # Check for correct case sensitivity selection (this check
-        # only works for non-windows os)
+        # only works on non-Windows OSes).
         with _common.system_mock('Darwin'):
             # exists = True and samefile = True => Case insensitive
             q = makeq()
             self.assertEqual(q.case_sensitive, False)
 
-            self.patcher_samefile.stop()
-            self.patcher_samefile.start().return_value = False
-
             # exists = True and samefile = False => Case sensitive
-            q = makeq()
-            self.assertEqual(q.case_sensitive, True)
-
             self.patcher_samefile.stop()
-            self.patcher_samefile.start().return_value = True
+            self.patcher_samefile.start().return_value = False
+            try:
+                q = makeq()
+                self.assertEqual(q.case_sensitive, True)
+            finally:
+                self.patcher_samefile.stop()
+                self.patcher_samefile.start().return_value = True
 
-        # test platform-aware default sensitivity when the library
-        # path does not exist (exist = False)
+        # Test platform-aware default sensitivity when the library path
+        # does not exist. For the duration of this check, we change the
+        # `os.path.exists` mock to return False.
         self.patcher_exists.stop()
         self.patcher_exists.start().return_value = False
-        with _common.system_mock('Darwin'):
-            q = makeq()
-            self.assertEqual(q.case_sensitive, True)
+        try:
+            with _common.system_mock('Darwin'):
+                q = makeq()
+                self.assertEqual(q.case_sensitive, True)
 
-        with _common.system_mock('Windows'):
-            q = makeq()
-            self.assertEqual(q.case_sensitive, False)
-        self.patcher_exists.stop()
-        self.patcher_exists.start().return_value = True
+            with _common.system_mock('Windows'):
+                q = makeq()
+                self.assertEqual(q.case_sensitive, False)
+        finally:
+            # Restore the `os.path.exists` mock to its original state.
+            self.patcher_exists.stop()
+            self.patcher_exists.start().return_value = True
 
     @patch('beets.library.os')
     def test_path_sep_detection(self, mock_os):