Merge from 3.x: PR #6530

Fixes #4231

spyder/widgets/sourcecode/codeeditor.py

@@ -924,9 +924,14 @@ def get_current_object(self):
 
     @Slot()
     def delete(self):
-        """Remove selected text"""
-        if self.has_selected_text():
-            self.remove_selected_text()
+        """Remove selected text or next character."""
+        if not self.has_selected_text():
+            cursor = self.textCursor()
+            position = cursor.position()
+            if not cursor.atEnd():
+                cursor.setPosition(position + 1, QTextCursor.KeepAnchor)
+            self.setTextCursor(cursor)
+        self.remove_selected_text()
 
     #------Find occurrences
     def __find_first(self, text):

spyder/widgets/sourcecode/tests/test_codeeditor.py

@@ -0,0 +1,75 @@
+# -*- coding: utf-8 -*-
+#
+# Copyright © Spyder Project Contributors
+# Licensed under the terms of the MIT License
+#
+
+"""
+Tests for codeeditor.py.
+"""
+
+try:
+    from unittest.mock import Mock
+except ImportError:
+    from mock import Mock  # Python 2
+
+# Third party imports
+import pytest
+from qtpy.QtGui import QTextCursor
+
+# Local imports
+from spyder import version_info
+import spyder.widgets.sourcecode.codeeditor as codeeditor
+
+
+@pytest.fixture
+def code_editor_bot(qtbot):
+    """Create code editor with default Python code."""
+    editor = codeeditor.CodeEditor(parent=None)
+    indent_chars = ' ' * 4
+    tab_stop_width_spaces = 4
+    editor.setup_editor(language='Python', indent_chars=indent_chars,
+                        tab_stop_width_spaces=tab_stop_width_spaces)
+    # Mock the screen updates and signal emits to test when they've been
+    # called.
+    editor.linenumberarea = Mock()
+    if version_info > (4, ):
+        editor.sig_flags_changed = Mock()
+    else:
+        editor.get_linenumberarea_width = Mock(return_value=1)
+    editor.breakpoints_changed = Mock()
+    return editor, qtbot
+
+
+# --- Tests
+# -----------------------------------------------------------------------------
+def test_delete(code_editor_bot, mocker):
+    """Test CodeEditor.delete()."""
+    editor, qtbot = code_editor_bot
+    text = ('def f1(a, b):\n')
+    editor.set_text(text)
+
+    # Move to start and delete next character without selection.
+    cursor = editor.textCursor()
+    cursor.movePosition(QTextCursor.Start)
+    editor.setTextCursor(cursor)
+    editor.delete()
+    assert editor.get_text_line(0) == 'ef f1(a, b):'
+
+    # Delete selection.
+    cursor = editor.textCursor()
+    cursor.select(QTextCursor.WordUnderCursor)
+    editor.setTextCursor(cursor)
+    editor.delete()
+    assert editor.get_text_line(0) == ' f1(a, b):'
+
+    # Move to end of document - nothing to delete after cursor.
+    cursor = editor.textCursor()
+    cursor.movePosition(QTextCursor.End)
+    editor.setTextCursor(cursor)
+    editor.delete()
+    assert editor.get_text_line(0) == ' f1(a, b):'
+
+
+if __name__ == "__main__":
+    pytest.main()