Add test

Author: danielhollas

Lib/_pyrepl/completing_reader.py

@@ -258,12 +258,13 @@ def after_command(self, cmd: Command) -> None:
     def calc_complete_screen(self) -> list[str]:
         screen = super().calc_complete_screen()
         if self.cmpltn_menu_visible:
+            # We display the completions menu below the current prompt
             ly = self.lxy[1] + 1
             screen[ly:ly] = self.cmpltn_menu
-            # This is a horrible hack. If we're not in the middle
-            # of multiline edit, don't append to screeninfo
-            # since that screws up the position calculation
-            # in pos2xy function.
+            # If we're not in the middle of multiline edit, don't append to screeninfo
+            # since that screws up the position calculation in pos2xy function.
+            # This is a hack to prevent the cursor jumping
+            # into the completions menu when pressing left or down arrow.
             if self.pos != len(self.buffer):
                 self.screeninfo[ly:ly] = [(0, [])]*len(self.cmpltn_menu)
         return screen

Lib/test/test_pyrepl/test_pyrepl.py

@@ -546,7 +546,7 @@ def test_global_namespace_completion(self):
         output = multiline_input(reader, namespace)
         self.assertEqual(output, "python")
 
-    def test_updown_arrow_with_completion_menu(self):
+    def test_up_down_arrow_with_completion_menu(self):
         """Up arrow in the middle of unfinished tab completion when the menu is displayed
         should work and trigger going back in history. Down arrow should subsequently
         get us back to the incomplete command."""
@@ -571,6 +571,30 @@ def test_updown_arrow_with_completion_menu(self):
         output = multiline_input(reader, namespace)
         self.assertEqual(output, "os.")
 
+    # TODO: This test doesn't seem to work as intended, it always succeeds
+    def test_right_down_arrows_with_completion_menu(self):
+        """Right / Down arrows while the tab completion menu is displayed
+        should do nothing"""
+        code = "os.\t\t"
+        namespace = {"os": os}
+
+        events = itertools.chain(
+            code_to_events(code),
+            [
+                Event(evt="key", data="down", raw=bytearray(b"\x1bOB")),
+                Event(evt="key", data="right", raw=bytearray(b"\x1bOC")),
+            ],
+            code_to_events("\n")
+        )
+        reader = self.prepare_reader(events, namespace=namespace)
+        output = multiline_input(reader, namespace)
+        self.assertEqual(output, "os.")
+        # When we press right and/or down arrow while
+        # the completions menu is displayed,
+        # the cursor should stay where it was on the line.
+        self.assertEqual(reader.cmpltn_menu_vis, 1)
+        self.assertEqual(reader.cxy, (6, 0))
+
     @patch("_pyrepl.readline._ReadlineWrapper.get_reader")
     @patch("sys.stderr", new_callable=io.StringIO)
     def test_completion_with_warnings(self, mock_stderr, mock_get_reader):