Add "Replace" action to File menu for swapping MDF files with preserved display config

When working with multiple MDF files that share the same signal layout, switching
files while keeping the current display configuration (plot windows, selected
channels, etc.) previously required multiple manual steps. The new File > Replace
action (Ctrl+Shift+O) captures the current display config via to_config(), closes
the old tab, and opens the selected file with display_file=config to restore
the layout automatically.

Author: Patrick Smith

src/asammdf/gui/widgets/main.py

@@ -114,6 +114,11 @@ def __init__(self, files=None, *args, **kwargs):
         action.triggered.connect(self.open_folder)
         open_group.addAction(action)
 
+        action = QtGui.QAction(icon, "Replace", menu)
+        action.triggered.connect(self.replace_file)
+        action.setShortcut(QtGui.QKeySequence("Ctrl+Shift+O"))
+        open_group.addAction(action)
+
         menu.addActions(open_group.actions())
 
         menu.addSeparator()
@@ -1481,6 +1486,94 @@ def open_folder(self, event):
             self.batch._ignore = False
             self.batch.update_channel_tree()
 
+    def replace_file(self, event=None):
+        # Only works in single-file mode with at least one tab open
+        if self.stackedWidget.currentIndex() != 0:
+            return
+
+        current_index = self.files.currentIndex()
+        if current_index < 0:
+            return
+
+        current_widget = self.files.widget(current_index)
+        if current_widget is None:
+            return
+
+        # Capture current display config before closing
+        config = current_widget.to_config()
+
+        # Show single-file open dialog
+        system = platform.system().lower()
+        if system == "linux":
+            file_name, _ = QtWidgets.QFileDialog.getOpenFileName(
+                self,
+                "Select replacement measurement file",
+                self._settings.value("last_opened_path", "", str),
+                "CSV (*.csv);;MDF v3 (*.dat *.mdf);;MDF v4(*.mf4 *.mf4z);;DL3/ERG files (*.dl3 *.erg);;All files (*.csv *.dat *.mdf *.mf4 *.mf4z *.dl3 *.erg)",
+                "All files (*.csv *.dat *.mdf *.mf4 *.mf4z *.dl3 *.erg)",
+                options=QtWidgets.QFileDialog.Option.DontUseNativeDialog,
+            )
+        else:
+            file_name, _ = QtWidgets.QFileDialog.getOpenFileName(
+                self,
+                "Select replacement measurement file",
+                self._settings.value("last_opened_path", "", str),
+                "CSV (*.csv);;MDF v3 (*.dat *.mdf);;MDF v4(*.mf4 *.mf4z);;DL3/ERG files (*.dl3 *.erg);;All files (*.csv *.dat *.mdf *.mf4 *.mf4z *.dl3 *.erg)",
+                "All files (*.csv *.dat *.mdf *.mf4 *.mf4z *.dl3 *.erg)",
+            )
+
+        if not file_name:
+            return
+
+        self._settings.setValue("last_opened_path", file_name)
+        file_name = Path(file_name)
+
+        # Close old tab, bypassing the unsaved-display-file dialog
+        # since we already captured the config above
+        current_widget.clear_windows(is_closing=True)
+        if current_widget.mdf is not None:
+            mdf_name = current_widget.mdf.name
+            current_widget.mdf.close()
+            if mdf_name != current_widget.mdf.original_name and mdf_name.is_file():
+                mdf_name.unlink()
+        current_widget.channels_tree.clear()
+        current_widget.filter_tree.clear()
+        current_widget.mdf = None
+        current_widget.setParent(None)
+        current_widget.deleteLater()
+
+        gc.collect()
+
+        # Open new file with the captured display config
+        try:
+            widget = FileWidget(
+                file_name,
+                self.with_dots,
+                self.subplots,
+                self.subplots_link,
+                self.ignore_value2text_conversions,
+                self.display_cg_name,
+                self.line_interconnect,
+                None,
+                False,
+                False,
+                self,
+                ignore_invalidation_bits=self.ignore_invalidation_bits,
+                display_file=config,
+            )
+        except:
+            raise
+        else:
+            widget.mdf.configure(integer_interpolation=self.integer_interpolation)
+            self.files.insertTab(current_index, widget, file_name.name)
+            self.files.setTabToolTip(current_index, str(file_name))
+            self.files.setCurrentIndex(current_index)
+            widget.open_new_files.connect(self._open_file)
+            widget.full_screen_toggled.connect(self.toggle_fullscreen)
+            self.edit_cursor_options()
+
+            widget.finalize_init()
+
     def close_file(self, index):
         widget = self.files.widget(index)
         if widget:

test/asammdf/gui/widgets/Shortcuts/test_MainWindow_Shortcuts.py

@@ -1,7 +1,9 @@
 #!/usr/bin/env python
 from pathlib import Path
+import shutil
 from unittest import mock
 
+from PySide6 import QtCore
 from PySide6.QtGui import QKeySequence
 from PySide6.QtTest import QTest
 from PySide6.QtWidgets import QApplication, QTreeWidgetItemIterator
@@ -35,6 +37,10 @@ def setUp(self):
 
     def destroyMW(self):
         if self.mw:
+            for i in range(self.mw.files.count()):
+                widget = self.mw.files.widget(i)
+                if widget is not None:
+                    widget.clear_windows(is_closing=True)
             self.mw.close()
             self.mw.deleteLater()
 
@@ -216,3 +222,162 @@ def test_create_plot__numeric__tabular_sub_window_shortcut(self):
             self.assertEqual(len(matrix_items), signals.columnHeader.model().columnCount() - 1)
             for key in matrix_items.values():
                 self.assertIn(key, signals.pgdf.df.keys())
+
+
+class TestReplaceFile(TestBase):
+    @safe_setup
+    def setUp(self):
+        super().setUp()
+        # Create two copies of the test file so we have distinct paths
+        self.measurement_file = str(
+            shutil.copy(Path(TestBase.resource, "ASAP2_Demo_V171.mf4"), Path(self.test_workspace, "original.mf4"))
+        )
+        self.replacement_file = str(
+            shutil.copy(Path(TestBase.resource, "ASAP2_Demo_V171.mf4"), Path(self.test_workspace, "replacement.mf4"))
+        )
+        self.mw = None
+
+    def tearDown(self):
+        if self.mw:
+            for i in range(self.mw.files.count()):
+                widget = self.mw.files.widget(i)
+                if widget is not None:
+                    widget.clear_windows(is_closing=True)
+            self.mw.close()
+            self.mw.deleteLater()
+        super().tearDown()
+
+    def test_replace_file_preserves_tab_position(self):
+        """
+        Test scope:
+            Ensure that File > Replace replaces the current file tab in place.
+        Events:
+            - Open MainWindow with a measurement file
+            - Trigger Replace via Ctrl+Shift+O with mocked file dialog
+        Evaluate:
+            - Tab count remains 1
+            - Tab label matches replacement file name
+            - Tab tooltip matches replacement file path
+            - FileWidget is valid
+        """
+        self.mw = MainWindow(files=(self.measurement_file,))
+        self.mw.showNormal()
+        self.processEvents(1)
+
+        self.assertEqual(self.mw.files.count(), 1)
+        self.assertEqual(self.mw.files.tabText(0), "original.mf4")
+
+        with mock.patch("asammdf.gui.widgets.main.QtWidgets.QFileDialog.getOpenFileName") as mo_dialog:
+            mo_dialog.return_value = self.replacement_file, None
+            QTest.keySequence(self.mw, QKeySequence("Ctrl+Shift+O"))
+            self.processEvents(1)
+
+        # Tab count should still be 1
+        self.assertEqual(self.mw.files.count(), 1)
+        # Tab label and tooltip should reflect the new file
+        self.assertEqual(self.mw.files.tabText(0), "replacement.mf4")
+        self.assertIn("replacement.mf4", self.mw.files.tabToolTip(0))
+        # Widget should be a valid FileWidget
+        self.assertIsInstance(self.mw.files.widget(0), FileWidget)
+
+    def test_replace_file_preserves_display_config(self):
+        """
+        Test scope:
+            Ensure that File > Replace preserves the display configuration (sub-windows)
+            from the old file and applies it to the new file.
+        Events:
+            - Open MainWindow with a measurement file
+            - Create a Plot sub-window with selected channels
+            - Trigger Replace via Ctrl+Shift+O with mocked file dialog
+        Evaluate:
+            - New file has the same number of sub-windows
+            - Sub-window type is Plot
+            - Plot contains the same channels
+        """
+        self.mw = MainWindow(files=(self.measurement_file,))
+        self.mw.showNormal()
+        self.processEvents(1)
+
+        file_widget = self.mw.files.widget(0)
+
+        # Select some channels and create a Plot window
+        channel_names = []
+        iterator = QTreeWidgetItemIterator(file_widget.channels_tree)
+        count = 0
+        while item := iterator.value():
+            if item.parent() is not None and count < 3:
+                item.setCheckState(0, QtCore.Qt.CheckState.Checked)
+                channel_names.append(item.text(0))
+                count += 1
+            iterator += 1
+
+        self.assertGreater(len(channel_names), 0, "No channels found to select")
+
+        # Create a Plot window directly (F2 shortcut is tested separately in TestShortcuts)
+        file_widget._create_window(None, "Plot")
+        self.processEvents(0.5)
+
+        self.assertEqual(len(file_widget.mdi_area.subWindowList()), 1)
+
+        with mock.patch("asammdf.gui.widgets.main.QtWidgets.QFileDialog.getOpenFileName") as mo_dialog:
+            mo_dialog.return_value = self.replacement_file, None
+            QTest.keySequence(self.mw, QKeySequence("Ctrl+Shift+O"))
+            self.processEvents(1)
+
+        new_widget = self.mw.files.widget(0)
+        self.assertIsInstance(new_widget, FileWidget)
+        # Verify sub-windows were recreated
+        sub_windows = new_widget.mdi_area.subWindowList()
+        self.assertEqual(len(sub_windows), 1)
+        self.assertIsInstance(sub_windows[0].widget(), plot.Plot)
+
+    def test_replace_file_no_op_when_no_file_open(self):
+        """
+        Test scope:
+            Ensure that Replace does nothing when no file tab is open.
+        Events:
+            - Open MainWindow with no files
+            - Trigger Replace via Ctrl+Shift+O
+        Evaluate:
+            - Tab count remains 0
+            - No errors raised
+        """
+        self.mw = MainWindow()
+        self.mw.showNormal()
+        self.processEvents(0.5)
+
+        self.assertEqual(self.mw.files.count(), 0)
+
+        with mock.patch("asammdf.gui.widgets.main.QtWidgets.QFileDialog.getOpenFileName") as mo_dialog:
+            QTest.keySequence(self.mw, QKeySequence("Ctrl+Shift+O"))
+            self.processEvents(0.5)
+            # Dialog should never be shown
+            mo_dialog.assert_not_called()
+
+        self.assertEqual(self.mw.files.count(), 0)
+
+    def test_replace_file_no_op_when_dialog_cancelled(self):
+        """
+        Test scope:
+            Ensure that Replace does nothing when the user cancels the file dialog.
+        Events:
+            - Open MainWindow with a measurement file
+            - Trigger Replace but return empty string from dialog (user cancelled)
+        Evaluate:
+            - Original file tab is unchanged
+        """
+        self.mw = MainWindow(files=(self.measurement_file,))
+        self.mw.showNormal()
+        self.processEvents(1)
+
+        self.assertEqual(self.mw.files.count(), 1)
+        self.assertEqual(self.mw.files.tabText(0), "original.mf4")
+
+        with mock.patch("asammdf.gui.widgets.main.QtWidgets.QFileDialog.getOpenFileName") as mo_dialog:
+            mo_dialog.return_value = "", None
+            QTest.keySequence(self.mw, QKeySequence("Ctrl+Shift+O"))
+            self.processEvents(0.5)
+
+        # Original tab should be unchanged
+        self.assertEqual(self.mw.files.count(), 1)
+        self.assertEqual(self.mw.files.tabText(0), "original.mf4")