diff --git a/spyder/app/tests/test_mainwindow.py b/spyder/app/tests/test_mainwindow.py
index 69ae625bb1d..0198a9f5020 100644
--- a/spyder/app/tests/test_mainwindow.py
+++ b/spyder/app/tests/test_mainwindow.py
@@ -349,12 +349,12 @@ def test_single_instance_and_edit_magic(main_window, qtbot, tmpdir):
 
     spy_dir = osp.dirname(get_module_path('spyder'))
     lock_code = ("import sys\n"
-                 "sys.path.append('{}')\n"
+                 "sys.path.append(r'{spy_dir_str}')\n"
                  "from spyder.config.base import get_conf_path\n"
                  "from spyder.utils.external import lockfile\n"
                  "lock_file = get_conf_path('spyder.lock')\n"
                  "lock = lockfile.FilesystemLock(lock_file)\n"
-                 "lock_created = lock.lock()".format(spy_dir))
+                 "lock_created = lock.lock()".format(spy_dir_str=spy_dir))
 
     # Test single instance
     with qtbot.waitSignal(shell.executed):
diff --git a/spyder/widgets/github/backend.py b/spyder/widgets/github/backend.py
index 9d0b3f28fdd..2493f93259c 100644
--- a/spyder/widgets/github/backend.py
+++ b/spyder/widgets/github/backend.py
@@ -142,8 +142,8 @@ def send_report(self, title, body, application_log=None):
             repo = gh.repos(self.gh_owner)(self.gh_repo)
             ret = repo.issues.post(title=title, body=body)
         except github.ApiError as e:
-            _logger().warn('failed to send bug report on github. response=%r' %
-                           e.response)
+            _logger().warning('Failed to send bug report on Github. '
+                              'response=%r', e.response)
             # invalid credentials
             if e.response.code == 401:
                 if self._show_msgbox:
@@ -287,7 +287,7 @@ def upload_log_file(self, log_content):
                 files={'SpyderIDE.log': {"content": log_content}})
             qApp.restoreOverrideCursor()
         except github.ApiError:
-            _logger().warn('failed to upload log report as a gist')
-            return '"failed to upload log file as a gist"'
+            _logger().warning('Failed to upload log report as a gist')
+            return '"Failed to upload log file as a gist"'
         else:
             return ret['html_url']
diff --git a/spyder/widgets/tests/test_editor.py b/spyder/widgets/tests/test_editor.py
index 0b57b67703d..a9bf593b44b 100644
--- a/spyder/widgets/tests/test_editor.py
+++ b/spyder/widgets/tests/test_editor.py
@@ -323,6 +323,7 @@ def test_replace_enter_press(editor_find_replace_bot):
     qtbot.keyPress(finder.search_text, Qt.Key_Return, modifier=Qt.ShiftModifier)
     assert editor.get_cursor_line_column() == (3,4)
 
+
 def test_replace_plain_regex(editor_find_replace_bot):
     """Test that regex reserved characters are displayed as plain text."""
     editor_stack, editor, finder, qtbot = editor_find_replace_bot
@@ -332,10 +333,11 @@ def test_replace_plain_regex(editor_find_replace_bot):
     finder.show()
     finder.show_replace()
     qtbot.keyClicks(finder.search_text, 'spam')
-    qtbot.keyClicks(finder.replace_text, '.\[()]*test')
+    qtbot.keyClicks(finder.replace_text, r'.\[()]*test')
     qtbot.keyPress(finder.replace_text, Qt.Key_Return)
     assert editor.toPlainText()[0:-1] == expected_new_text
 
+
 def test_replace_invalid_regex(editor_find_replace_bot):
     """Assert that replacing an invalid regexp does nothing."""
     editor_stack, editor, finder, qtbot = editor_find_replace_bot
diff --git a/spyder/widgets/variableexplorer/arrayeditor.py b/spyder/widgets/variableexplorer/arrayeditor.py
index 466c2915dcf..261bd081384 100644
--- a/spyder/widgets/variableexplorer/arrayeditor.py
+++ b/spyder/widgets/variableexplorer/arrayeditor.py
@@ -780,11 +780,11 @@ def change_active_widget(self, index):
         slice_index[self.last_dim] = data_index
 
         stack_index = self.dim_indexes[self.last_dim].get(data_index)
-        if stack_index == None:
+        if stack_index is None:
             stack_index = self.stack.count()
             try:
-                self.stack.addWidget(ArrayEditorWidget(self,
-                                                       self.data[slice_index]))
+                self.stack.addWidget(ArrayEditorWidget(
+                    self, self.data[tuple(slice_index)]))
             except IndexError:  # Handle arrays of size 0 in one axis
                 self.stack.addWidget(ArrayEditorWidget(self, self.data))
             self.dim_indexes[self.last_dim][data_index] = stack_index
diff --git a/spyder/widgets/variableexplorer/collectionseditor.py b/spyder/widgets/variableexplorer/collectionseditor.py
index 92dccf9d217..56ffe876ad4 100644
--- a/spyder/widgets/variableexplorer/collectionseditor.py
+++ b/spyder/widgets/variableexplorer/collectionseditor.py
@@ -192,17 +192,23 @@ def set_size_and_type(self, start=None, stop=None):
             fetch_more = False
         else:
             fetch_more = True
-        
-        if self.remote:
-            sizes = [ data[self.keys[index]]['size'] 
-                      for index in range(start, stop) ]
-            types = [ data[self.keys[index]]['type']
-                      for index in range(start, stop) ]
-        else:
-            sizes = [ get_size(data[self.keys[index]])
-                      for index in range(start, stop) ]
-            types = [ get_human_readable_type(data[self.keys[index]])
-                      for index in range(start, stop) ]
+
+        # Ignore pandas warnings that certain attributes are deprecated
+        # and will be removed, since they will only be accessed if they exist.
+        with warnings.catch_warnings():
+            warnings.filterwarnings(
+                "ignore", message=(r"^\w+\.\w+ is deprecated and "
+                                   "will be removed in a future version"))
+            if self.remote:
+                sizes = [data[self.keys[index]]['size']
+                         for index in range(start, stop)]
+                types = [data[self.keys[index]]['type']
+                         for index in range(start, stop)]
+            else:
+                sizes = [get_size(data[self.keys[index]])
+                         for index in range(start, stop)]
+                types = [get_human_readable_type(data[self.keys[index]])
+                         for index in range(start, stop)]
 
         if fetch_more:
             self.sizes = self.sizes + sizes